Electricity is a chapter in the CBSE Class 10 Science syllabus from Science. This chapter hub brings together revision notes, practice questions, worksheets, flashcards, formula sheet to help students learn, practice, and revise Electricity effectively.

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Electricity

NCERT Class 10 Science Chapter 11: Electricity (Pages 171–194)

Summary of Electricity

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Electricity at a Glance

Board

CBSE

Class

Class 10

Subject

Science

Book

Science

Chapter

11

Pages

171194

Resources

7 study resources

Electricity Summary

In this chapter, students explore the concept of electricity, starting with its importance in modern society as a manageable and versatile energy source. Electricity is critical in homes, schools, hospitals, and industries, illustrating its role in daily life. The chapter begins by defining electric current, which is the flow of electric charge through a conductor, similar to the flow of water in pipes. The continuous path through which current flows is called an electric circuit, and it requires a closed loop to function, much like completing a circuit in a device like a torch. When the switch is off, the circuit is open, and the current stops, causing the bulb to go dark. Key to understanding electricity is the distinction between electric charge and current; electric charge is measured in coulombs, while current, defined as the rate of flow of charge, is measured in amperes. Students learn how to measure current using an ammeter, which must be connected in series to read correctly. The chapter also discusses electric potential difference or voltage, which is necessary to move charges through a circuit. This potential difference is essential for establishing the flow of current, akin to pressure in a water system. Volts measure this potential difference, and students become familiar with voltmeters used to measure voltage. The chapter emphasizes Ohm's Law, which states that the current through a conductor between two points is directly proportional to the potential difference across the two points. This relationship is foundational in circuit analysis. Following this, the chapter investigates factors affecting resistance in conductors, including length, cross-sectional area, and material. Understanding resistance is crucial as it affects how easily current can flow through different materials. Additionally, students learn about series and parallel resistors, including their combined effects on current and voltage in circuits, enhancing their comprehension of more complex circuit designs. Practical applications of electrical concepts, such as heating effects in devices like toasters and electric irons, illustrate the chapter's relevance. Finally, the chapter concludes by exploring electric power, highlighting how it is calculated and measured, crucial knowledge for understanding energy consumption in electrical devices.

Electricity Revision Guide

Download the Electricity revision guide with key points, summaries, and quick revision notes for CBSE Class 10 Science.

Key Points

1

Define electric current.

Electric current is the flow of electric charge. It's measured in amperes (A). In metallic conductors, it's due to electron flow.

2

State Ohm's Law.

Ohm's Law states V=IR, where V is potential difference, I is current, and R is resistance. It's valid when temperature remains constant.

3

Explain electric potential difference.

Potential difference is the work done to move a unit charge between two points. It's measured in volts (V) and drives current flow.

4

Describe resistors in series.

In series, resistors' equivalent resistance is the sum of individual resistances. Current remains same across all resistors.

5

Describe resistors in parallel.

In parallel, reciprocal of equivalent resistance is sum of reciprocals of individual resistances. Voltage remains same across all resistors.

6

Define electrical power.

Electrical power is the rate at which electrical energy is consumed. It's calculated as P=VI and measured in watts (W).

7

Explain Joule's law of heating.

Heat produced in a resistor is directly proportional to square of current (I²), resistance (R), and time (t): H=I²Rt.

8

State the unit of electrical energy.

Commercial unit of electrical energy is kilowatt-hour (kWh), which equals 3.6×10⁶ joules. It's used for billing purposes.

9

Explain factors affecting resistance.

Resistance depends on material (ρ), length (l), and cross-sectional area (A): R=ρl/A. It increases with temperature for metals.

10

Describe electric circuit symbols.

Standard symbols represent components like cells, bulbs, switches, resistors, ammeters, and voltmeters in circuit diagrams.

11

Explain ammeter and voltmeter connections.

Ammeter is connected in series to measure current. Voltmeter is connected in parallel to measure potential difference.

12

Define resistivity.

Resistivity (ρ) is a material property indicating how strongly it opposes current. Unit is ohm-meter (Ωm). It's temperature-dependent.

13

Explain fuse function.

Fuse is a safety device that melts when current exceeds rated value, breaking the circuit to prevent damage.

14

Describe heating effect applications.

Used in appliances like heaters, toasters, and bulbs. Tungsten filaments in bulbs glow white-hot due to heating effect.

15

Explain why alloys are used in heating devices.

Alloys have high resistivity and don't oxidize easily at high temperatures, making them ideal for heating elements.

16

Calculate energy consumption.

Energy (E) = Power (P) × Time (t). For a 100W device used for 2 hours, E=0.1kW×2h=0.2kWh.

17

Explain why copper is used in wiring.

Copper has low resistivity, is ductile, and doesn't corrode easily, making it ideal for electrical wiring.

18

Describe dangers of short circuits.

Short circuits cause excessive current flow, leading to overheating and potential fires. Fuses/circuit breakers prevent this.

19

Explain parallel vs series in homes.

Home appliances are connected in parallel so each operates independently at same voltage, unlike series connections.

20

Calculate equivalent resistance.

For two resistors R₁ and R₂: Series Rₑ=R₁+R₂; Parallel Rₑ=(R₁R₂)/(R₁+R₂). Example: 2Ω & 3Ω in parallel gives 1.2Ω.

Electricity Practice Questions & Answers

Practice important questions and exam-style problems from Electricity. These questions cover key topics from the CBSE Class 10 Science syllabus.

How to practice: Start with the questions below to test your understanding of Electricity. Use the revision guide to review concepts you find difficult, then come back and retry the questions for better retention.

View all 495 Electricity questions
Q9

What is the role of an ammeter in a circuit?

Single Answer MCQ
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Q10

Explain the concept of electric power.

Single Answer MCQ
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Q11

How does the resistance of a conductor change with temperature?

Single Answer MCQ
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Q12

Define the term 'electric circuit'.

Single Answer MCQ
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Q13

What is the purpose of using an insulator in an electrical circuit?

Single Answer MCQ
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Q14

Differentiate between conductors and insulators.

Single Answer MCQ
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Q15

How does the resistance of a conductor change with its material?

Single Answer MCQ
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Q16

Describe the construction and working of an electric cell.

Single Answer MCQ
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Q17

What is the significance of earthing in electrical installations?

Single Answer MCQ
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Q18

Explain the concept of electric potential difference.

Single Answer MCQ
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Q19

How does the resistance of a conductor change with its thickness?

Single Answer MCQ
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Q20

What is the role of a voltmeter in an electrical circuit?

Single Answer MCQ
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Q21

Define the term 'electric current'.

Single Answer MCQ
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Q22

Explain the concept of electrical energy.

Single Answer MCQ
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Q23

How does the resistance of a conductor change with its temperature?

Single Answer MCQ
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Q24

Describe the working principle of an electric heater.

Single Answer MCQ
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Q25

What is the SI unit of electric current?

Single Answer MCQ
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Q26

Define electric potential.

Single Answer MCQ
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Q27

What is the SI unit of electric potential difference?

Single Answer MCQ
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Q28

What does a voltmeter measure?

Single Answer MCQ
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Q29

If a charge of 3 coulombs is moved through a potential difference of 6 volts, how much work is done?

Single Answer MCQ
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Q30

Which of the following statements best describes electric potential difference?

Single Answer MCQ
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Q31

In a circuit, if the potential difference across a resistor is doubled, what happens to the current, assuming resistance remains constant?

Single Answer MCQ
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Q32

What is the work done in moving a charge of 5 C through a potential difference of 10 V?

Single Answer MCQ
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Q33

How is potential difference maintained in a circuit?

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Q34

Which of the following correctly defines 1 volt?

Single Answer MCQ
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Q35

What happens to the potential difference when a battery is connected to a circuit?

Single Answer MCQ
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Q36

What is the formula used to calculate electric potential difference?

Single Answer MCQ
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Q37

If the potential difference across two points is 12V and a charge of 4C is moved, how much work is done?

Single Answer MCQ
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Q38

What role does chemical energy play in a battery?

Single Answer MCQ
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Q39

What symbol is used to represent an electric cell in a circuit diagram?

Single Answer MCQ
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Q40

Which condition must be true for charge to flow in a conductor?

Single Answer MCQ
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Q41

In a circuit diagram, what does a closed switch symbol indicate?

Single Answer MCQ
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Q42

Which of the following components is used to measure the current in a circuit?

Single Answer MCQ
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Q43

What is the purpose of a battery in a circuit?

Single Answer MCQ
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Q44

Which of the following symbols indicates a resistor in a circuit diagram?

Single Answer MCQ
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Q45

What happens to the total resistance in a parallel circuit as more resistors are added?

Single Answer MCQ
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Q46

If a circuit has a series configuration of two identical resistors, what is the relationship of total resistance?

Single Answer MCQ
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Q47

Which type of circuit would continue to function even if one component fails?

Single Answer MCQ
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Q48

What does the term 'potential difference' refer to in a circuit?

Single Answer MCQ
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Q49

In a circuit diagram, how are wires represented?

Single Answer MCQ
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Q50

What is the function of a switch in a circuit?

Single Answer MCQ
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Q51

What should you check first if a circuit does not work?

Single Answer MCQ
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Q52

What is the SI unit of electric current?

Single Answer MCQ
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Q53

If a circuit contains three resistors in parallel of values 6Ω, 12Ω, and 18Ω, what is the equivalent resistance?

Single Answer MCQ
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Q54

What path does electricity follow in a circuit?

Single Answer MCQ
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Q55

What is the main advantage of a parallel circuit compared to a series circuit?

Single Answer MCQ
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Q56

What does a switch do in an electric circuit?

Single Answer MCQ
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Q57

When drawing a circuit diagram, what is essential to include?

Single Answer MCQ
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Q58

How is electric current measured in a circuit?

Single Answer MCQ
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Q59

If 3 coulombs of charge flow through a circuit in 3 seconds, what is the current?

Single Answer MCQ
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Q60

What happens to current if the resistance in a circuit increases while voltage remains constant?

Single Answer MCQ
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Q61

Which of the following statements is true about conventional current?

Single Answer MCQ
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Q62

How many electrons make up one coulomb of charge?

Single Answer MCQ
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Q63

In a series circuit, if one component fails, what happens to the current?

Single Answer MCQ
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Q64

What is the relationship between voltage, current, and resistance called?

Single Answer MCQ
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Q65

If a current of 2 A flows for 5 minutes, how much charge flows through the circuit?

Single Answer MCQ
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Q66

Which component is essential for measuring current in a circuit?

Single Answer MCQ
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Q67

When the voltage in a circuit increases while resistance stays the same, what happens to the current?

Single Answer MCQ
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Q68

If the current flowing through a circuit is reversed, what happens to the functioning of the circuit?

Single Answer MCQ
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Q69

What is a potential reason for a bulb to not glow in an electric circuit?

Single Answer MCQ
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Q70

What does Ohm's Law state?

Single Answer MCQ
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Q71

If the voltage across a resistor is doubled, how does this affect the current, according to Ohm's Law?

Single Answer MCQ
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Q72

A circuit has a total resistance of 10 Ω and a current of 2 A. What is the voltage across the circuit?

Single Answer MCQ
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Q73

Which of the following represents the correct unit of resistance?

Single Answer MCQ
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Q74

If a resistor has a current of 3 A flowing through it and the voltage across it is 12 V, what is its resistance?

Single Answer MCQ
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Q75

A light bulb has a resistance of 60 Ω and is connected to a 120 V supply. What is the current flowing through the bulb?

Single Answer MCQ
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Q76

What is the equivalent resistance when two resistors of 4 Ω and 6 Ω are connected in series?

Single Answer MCQ
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Q77

In a circuit where current and resistance are directly proportional, what happens to the current if the resistance is tripled?

Single Answer MCQ
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Q78

If a wire's resistance is 10 Ω, what would be the total resistance in a parallel circuit with another wire of resistance 10 Ω?

Single Answer MCQ
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Q79

In an electric circuit, if the total voltage is 24 V and the total current is 3 A, what can be determined about the total resistance?

Single Answer MCQ
Q-00004508
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Q80

If you have a circuit with three resistors (3 Ω, 6 Ω, and 9 Ω) in series, what is the total resistance?

Single Answer MCQ
Q-00004509
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Q81

A circuit has three resistors: R1 = 4 Ω, R2 = 8 Ω, and R3 = 12 Ω in parallel. What is the equivalent resistance?

Single Answer MCQ
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Q82

How does temperature typically affect the resistance of a metallic conductor?

Single Answer MCQ
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Q83

If a current of 5 A flows through a 2 Ω resistor, what power is being dissipated by the resistor?

Single Answer MCQ
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Q84

What happens to the total resistance when resistors are connected in series?

Single Answer MCQ
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Q85

What is the equivalent resistance (R_eq) of two resistors with resistances R1 = 2Ω and R2 = 3Ω in series?

Single Answer MCQ
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Q86

Which statement about resistors in parallel is true?

Single Answer MCQ
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Q87

If resistors R1 = 4Ω, R2 = 6Ω are connected in parallel, what is the equivalent resistance?

Single Answer MCQ
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Q88

In a series circuit, how does the total current relate to individual resistors?

Single Answer MCQ
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Q89

If two resistors with values of 5Ω and 15Ω are connected in series, what would be their total resistance?

Single Answer MCQ
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Q90

What is the critical difference in how current flows when resistors are in parallel versus in series?

Single Answer MCQ
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Q91

A circuit has three resistors connected in parallel: 2Ω, 3Ω, and 6Ω. What is the total resistance?

Single Answer MCQ
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Q92

What happens to the equivalent resistance when more resistors are added in series?

Single Answer MCQ
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Q93

Which configuration allows for individual devices to operate independently without affecting one another?

Single Answer MCQ
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Q94

If you combine four resistors of 2Ω each in series, what is their total resistance?

Single Answer MCQ
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Q95

A circuit with resistors in parallel has a total voltage of 12V and resistor values of 4Ω, 6Ω, and 12Ω. What is the total current flowing through the circuit?

Single Answer MCQ
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Q96

Which of the following statements about resistors in series is NOT true?

Single Answer MCQ
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Q97

In a circuit where resistors are connected in series and one fails, what happens to the other resistors?

Single Answer MCQ
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Q98

For a parallel circuit with resistors of 3Ω and 6Ω, what is the total resistance?

Single Answer MCQ
Q-00004527
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Q99

A total resistance of 10Ω is formed by combining two resistors in series. If one resistor is 4Ω, what is the value of the other resistor?

Single Answer MCQ
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Q100

Which factor does NOT affect the resistance of a conductor?

Single Answer MCQ
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Q101

How does doubling the length of a wire affect its resistance?

Single Answer MCQ
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Q102

If the area of cross-section of a wire is increased, what happens to the resistance?

Single Answer MCQ
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Q103

Which of the following materials has the least resistance?

Single Answer MCQ
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Q104

Which property of a conductor is represented by the symbol 'ρ' (rho)?

Single Answer MCQ
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Q105

What happens to the resistance if the temperature of a conductor increases?

Single Answer MCQ
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Q106

If two wires of the same material have different lengths and cross-sectional areas, which one will have more resistance?

Single Answer MCQ
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Q107

What is the relationship described by Ohm's law regarding voltage, current, and resistance?

Single Answer MCQ
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Q108

In what type of material would you expect the resistance to be very high?

Single Answer MCQ
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Q109

With a constant potential difference, what effect does increasing resistance have on current?

Single Answer MCQ
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Q110

A nichrome wire and a copper wire of the same length and area are connected. What will be the effect on current?

Single Answer MCQ
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Q111

Which configuration would give you a total resistance greater than any individual resistor?

Single Answer MCQ
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Q112

What is the primary reason for the heating effect of electric current in a conductor?

Single Answer MCQ
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Q113

What phenomenon occurs if a material with very low resistivity is used in a circuit?

Single Answer MCQ
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Q114

Which device uses the heating effect of electric current to provide light?

Single Answer MCQ
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Q115

In what scenario might a conductor's resistivity change substantially?

Single Answer MCQ
Q-00004544
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Q116

If 5 A of current flows through a resistor for 10 seconds, how much heat is produced if the resistance is 4 Ohms?

Single Answer MCQ
Q-00004545
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Q117

What does a resistor do in an electric circuit?

Single Answer MCQ
Q-00004546
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Q118

Why does an electric heating element glow while its connecting wires do not?

Single Answer MCQ
Q-00004547
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Q119

Which formula represents electric power in terms of voltage and current?

Single Answer MCQ
Q-00004548
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Q120

If two resistors are connected in parallel, how does their total resistance compare to their individual resistances?

Single Answer MCQ
Q-00004549
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Q121

An electric kettle operates at 1500 W for 2 hours. How much energy does it consume?

Single Answer MCQ
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Q122

How is a fuse related to the heating effect of electric current?

Single Answer MCQ
Q-00004551
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Q123

What does a higher wattage rating indicate about an electrical device?

Single Answer MCQ
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Q124

An electric circuit is purely resistive. What happens to the energy supplied by the source?

Single Answer MCQ
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Q125

If a device requires 0.5 A at 220 V, what is its power?

Single Answer MCQ
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Q126

What is the unit of electrical resistance?

Single Answer MCQ
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Q127

Calculate the current in a circuit if a device operates at 1 kW and uses a voltage of 230 V.

Single Answer MCQ
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Q128

Using the formula H = VIt, what is the heat produced when 10 A current flows through a 120 V source for 5 seconds?

Single Answer MCQ
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Q129

What is the commercial unit of electrical energy typically used?

Single Answer MCQ
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Q130

In Joule's heating law, what effect does increasing the current have on heat produced?

Single Answer MCQ
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Q131

A fuse rated at 5 A will blow if the current exceeds what value?

Single Answer MCQ
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Q132

Which factor does NOT affect the heat produced in a resistor?

Single Answer MCQ
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Q133

If an electric appliance has a resistance of 10 Ω and operates at 5 A, what is the power?

Single Answer MCQ
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Q134

What happens to the heating element of an electric kettle during operation?

Single Answer MCQ
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Q135

A device consumes 2 kW of power for 3 hours. How much energy does it consume in kilowatt-hours?

Single Answer MCQ
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Q136

During a short circuit, what causes the fuse to blow?

Single Answer MCQ
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Q137

Which of the following is a common misconception about electric circuits?

Single Answer MCQ
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Q138

Which component is essential for converting electrical energy into heat in an electric iron?

Single Answer MCQ
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Q139

If a refrigerator uses 400 W and runs for 24 hours, how much energy does it use in kilowatt-hours?

Single Answer MCQ
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Q140

What describes the relationship between power, voltage, and resistance in an electric circuit?

Single Answer MCQ
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Q141

What would happen if the resistance in a circuit increases while voltage remains constant?

Single Answer MCQ
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Q142

What is the power consumed by an 800 W electric bike if it operates for 1.5 hours?

Single Answer MCQ
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Q143

How are watts related to joules in terms of time?

Single Answer MCQ
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Q144

What happens to the power in a circuit if both the voltage and current are doubled?

Single Answer MCQ
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Q145

What is the SI unit of electric potential difference?

Single Answer MCQ
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Q146

Which device is used to measure electric potential difference?

Single Answer MCQ
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Q147

What does a potential difference of 1 volt indicate?

Single Answer MCQ
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Q148

If a battery applies a potential difference of 12 V, how much work is done in moving 2 C of charge?

Single Answer MCQ
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Q149

Which of the following statements is NOT true about electric potential difference?

Single Answer MCQ
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Q150

What is the potential difference between two points when 5 Joules of work is done to move a charge of 5 Coulombs?

Single Answer MCQ
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Q151

How does the potential difference affect the flow of charges in a conductor?

Single Answer MCQ
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Q152

When connecting a battery to a circuit, what happens to the electric charges?

Single Answer MCQ
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Q153

If the potential difference across a conductor is doubled, what happens to the current flowing through it (assuming resistance stays constant)?

Single Answer MCQ
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Q154

What is the potential difference required to move a 2 C charge with 10 J of work done?

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Q155

What is the effect of increasing the resistance in a circuit while keeping the potential difference constant?

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Q156

If a 9V battery is connected to a circuit with a resistance of 3 ohms, what is the current flowing through the circuit?

Single Answer MCQ
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Q157

Which of the following statements about electric potential energy is correct?

Single Answer MCQ
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Q158

An electron moves from a region of low potential to high potential. What can be said about the work done?

Single Answer MCQ
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Q159

What is the role of electric potential difference in electrical circuits?

Single Answer MCQ
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Q160

What is the SI unit of electric current?

Single Answer MCQ
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Q161

Which of the following describes a closed electric circuit?

Single Answer MCQ
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Q162

What happens when a switch in a circuit is turned off?

Single Answer MCQ
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Q163

How is electric current defined?

Single Answer MCQ
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Q164

Which instrument is used to measure electric current?

Single Answer MCQ
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Q165

What does a parallel circuit allow for?

Single Answer MCQ
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Q166

If 2 coulombs of charge pass through a cross-section in 2 seconds, what is the current?

Single Answer MCQ
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Q167

In which direction does conventional current flow?

Single Answer MCQ
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Q168

What does an open circuit imply?

Single Answer MCQ
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Q169

What is the relationship between voltage, current, and resistance known as?

Single Answer MCQ
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Q170

How would the current change if the resistance in a circuit increases while voltage remains constant?

Single Answer MCQ
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Q171

What is the charge of one electron?

Single Answer MCQ
Q-00019294
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Q172

What is the effect of increasing the voltage in a circuit while keeping resistance constant?

Single Answer MCQ
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Q173

What term describes the flow of electric charge?

Single Answer MCQ
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Q174

If a circuit has an ammeter displaying 5 mA, how much current is flowing?

Single Answer MCQ
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Q175

What will happen if two batteries are connected in series?

Single Answer MCQ
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Q176

What symbol is used to represent a battery in a circuit diagram?

Single Answer MCQ
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Q177

Which of the following represents an open switch in a circuit diagram?

Single Answer MCQ
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View explanation
Q178

If a circuit includes a resistor, what does it indicate?

Single Answer MCQ
Q-00019301
View explanation
Q179

What does Ohm's Law state about the relationship between voltage, current, and resistance?

Single Answer MCQ
Q-00019302
View explanation
Q180

In a circuit diagram, what does a zigzag line represent?

Single Answer MCQ
Q-00019303
View explanation
Q181

A circuit has a resistance of 10 Ω and a current of 2 A flowing through it. What is the voltage across the circuit?

Single Answer MCQ
Q-00019304
View explanation
Q182

What is the total current when two resistors, 10 Ω and 20 Ω, are in series with a 30 V battery?

Single Answer MCQ
Q-00019305
View explanation
Q183

When the current flowing through a resistor is doubled, what happens to the voltage across it?

Single Answer MCQ
Q-00019306
View explanation
Q184

What happens when a switch in a circuit is closed?

Single Answer MCQ
Q-00019307
View explanation
Q185

If a resistor has a voltage of 15 V across it and the current flowing through it is 3 A, what is its resistance?

Single Answer MCQ
Q-00019308
View explanation
Q186

In a parallel circuit, what is true about the voltage across each resistor?

Single Answer MCQ
Q-00019309
View explanation
Q187

In a series circuit consisting of three resistors (4 Ω, 6 Ω, and 10 Ω), what is the total resistance?

Single Answer MCQ
Q-00019310
View explanation
Q188

What does a voltmeter measure in a circuit?

Single Answer MCQ
Q-00019311
View explanation
Q189

If the voltage is tripled in a circuit while keeping resistance constant, what happens to the current?

Single Answer MCQ
Q-00019312
View explanation
Q190

Which component is used to measure current in a circuit?

Single Answer MCQ
Q-00019313
View explanation
Q191

What is the correct unit of resistance?

Single Answer MCQ
Q-00019314
View explanation
Q192

If three resistors of 5 Ω, 10 Ω, and 15 Ω are in series, what is the total resistance?

Single Answer MCQ
Q-00019315
View explanation
Q193

Which of the following can interrupt the flow of electricity in a circuit?

Single Answer MCQ
Q-00019316
View explanation
Q194

An electric circuit has a voltage of 48 V and a total resistance of 12 Ω. What is the current in the circuit?

Single Answer MCQ
Q-00019317
View explanation
Q195

In a circuit diagram, what does a circle with a cross inside represent?

Single Answer MCQ
Q-00019318
View explanation
Q196

What occurs when the resistance in a circuit is increased while keeping the voltage constant?

Single Answer MCQ
Q-00019319
View explanation
Q197

When analyzing a circuit diagram, what does crossing lines without a dot signify?

Single Answer MCQ
Q-00019320
View explanation
Q198

If a 12 V battery is used in a circuit where the total resistance is 4 Ω, what is the power dissipated in the resistor?

Single Answer MCQ
Q-00019321
View explanation
Q199

In a parallel circuit, what happens to the total current when more branches are added?

Single Answer MCQ
Q-00019322
View explanation
Q200

Which of the following graphically represents Ohm's Law?

Single Answer MCQ
Q-00019323
View explanation
Q201

What do you call a circuit that uses more than one power source?

Single Answer MCQ
Q-00019324
View explanation
Q202

A wire has a resistance of 8 Ω and is connected to a 16 V battery. What is the current flowing through the wire?

Single Answer MCQ
Q-00019325
View explanation
Q203

What is the role of a rheostat in a circuit diagram?

Single Answer MCQ
Q-00019326
View explanation
Q204

What is the effective resistance of two resistors of 3 Ω and 6 Ω connected in series?

Single Answer MCQ
Q-00019327
View explanation
Q205

If the voltage across a device is decreased, how does this typically affect the current according to Ohm's Law?

Single Answer MCQ
Q-00019328
View explanation
Q206

In a parallel circuit with two branches of 4 Ω and 6 Ω, what is the equivalent resistance?

Single Answer MCQ
Q-00019329
View explanation
Q207

What is the equivalent resistance of two resistors R1 = 4 Ω and R2 = 6 Ω connected in series?

Single Answer MCQ
Q-00019330
View explanation
Q208

When resistors are connected in parallel, what happens to the total resistance?

Single Answer MCQ
Q-00019331
View explanation
Q209

Which of the following statements is true for resistors in series?

Single Answer MCQ
Q-00019332
View explanation
Q210

Calculate the total resistance of three resistors: 5 Ω, 10 Ω, and 15 Ω connected in parallel.

Single Answer MCQ
Q-00019333
View explanation
Q211

If a 12 Ω and a 3 Ω resistor are connected in series, what is their total resistance?

Single Answer MCQ
Q-00019334
View explanation
Q212

How does the current through each resistor in series compare?

Single Answer MCQ
Q-00019335
View explanation
Q213

What is the equivalent resistance of a 10 Ω and a 20 Ω resistor connected in parallel?

Single Answer MCQ
Q-00019336
View explanation
Q214

Which configuration allows for individual components to operate independently?

Single Answer MCQ
Q-00019337
View explanation
Q215

If a resistor of 8 Ω is placed in a circuit with a 24 V battery, what current flows through it?

Single Answer MCQ
Q-00019338
View explanation
Q216

What is a practical application of resistors connected in series?

Single Answer MCQ
Q-00019339
View explanation
Q217

What happens to the total resistance if more resistors are added in series?

Single Answer MCQ
Q-00019340
View explanation
Q218

For resistors in parallel, if one resistor fails, what happens to the circuit?

Single Answer MCQ
Q-00019341
View explanation
Q219

A circuit has three resistors of 2 Ω, 4 Ω, and 6 Ω connected in series. What is the total resistance?

Single Answer MCQ
Q-00019342
View explanation
Q220

What would be the total resistance of three identical resistors of 5 Ω each connected in series?

Single Answer MCQ
Q-00019343
View explanation
Q221

What does the resistance of a conductor depend on?

Single Answer MCQ
Q-00019344
View explanation
Q222

How does increasing the length of a wire affect its resistance?

Single Answer MCQ
Q-00019345
View explanation
Q223

If two wires of the same material are identical in length but one has twice the cross-sectional area, how does their resistance compare?

Single Answer MCQ
Q-00019346
View explanation
Q224

What is the relationship between resistivity and the resistance of the conductor?

Single Answer MCQ
Q-00019347
View explanation
Q225

If a copper wire and a tungsten wire are of the same length and cross-sectional area, which has higher resistance?

Single Answer MCQ
Q-00019348
View explanation
Q226

What effect does temperature have on the resistance of a conductor?

Single Answer MCQ
Q-00019349
View explanation
Q227

Which of the following materials would likely be the best conductor of electricity?

Single Answer MCQ
Q-00019350
View explanation
Q228

If the length of a conductor is doubled and its area of cross-section is halved, what will happen to its resistance?

Single Answer MCQ
Q-00019351
View explanation
Q229

What happens to the resistance if a material is found to have very low resistivity?

Single Answer MCQ
Q-00019352
View explanation
Q230

In which condition would a conductor have maximum resistance?

Single Answer MCQ
Q-00019353
View explanation
Q231

If the material of a wire is changed from copper to aluminum but its dimensions remain the same, what will happen to resistance?

Single Answer MCQ
Q-00019354
View explanation
Q232

If a resistor with constant resistance is connected to a circuit with higher voltage, what happens to the current?

Single Answer MCQ
Q-00019355
View explanation
Q233

What configuration can provide a lower equivalent resistance when combining resistors?

Single Answer MCQ
Q-00019356
View explanation
Q234

A wire is cut in half. If the two halves are connected in series, what happens to the total resistance compared to the original wire?

Single Answer MCQ
Q-00019357
View explanation
Q235

If you have two wires of the same material and length but different diameters, how does their resistance differ?

Single Answer MCQ
Q-00019358
View explanation
Q236

Which factor is least likely to affect the resistance of a conductor?

Single Answer MCQ
Q-00019359
View explanation
Q237

Which formula represents the heating effect of electric current?

Single Answer MCQ
Q-00019375
View explanation
Q238

What is the SI unit of electric current?

Single Answer MCQ
Q-00019376
View explanation
Q239

If an electric iron operates with a current of 4 A and a resistance of 10 Ω, what is the heat produced in 30 seconds?

Single Answer MCQ
Q-00019377
View explanation
Q240

In which of the following devices is the heating effect of electric current primarily used?

Single Answer MCQ
Q-00019378
View explanation
Q241

What happens to a fuse when it experiences a current above its rating?

Single Answer MCQ
Q-00019379
View explanation
Q242

Why does a heating element glow while the cord remains cool?

Single Answer MCQ
Q-00019380
View explanation
Q243

What type of energy conversion occurs with the heating effect of electric current?

Single Answer MCQ
Q-00019381
View explanation
Q244

Calculate the heat generated by transferring 96000 coulombs of charge across a potential difference of 50 V in one hour.

Single Answer MCQ
Q-00019382
View explanation
Q245

Which material is commonly used for making filaments in electric bulbs due to its high melting point?

Single Answer MCQ
Q-00019383
View explanation
Q246

What is the principle behind the operation of an electric heater?

Single Answer MCQ
Q-00019384
View explanation
Q247

How does increasing the resistance in a circuit impact the heating effect?

Single Answer MCQ
Q-00019385
View explanation
Q248

What is one major disadvantage of the heating effect of electric current in circuits?

Single Answer MCQ
Q-00019386
View explanation
Q249

Which of the following correctly describes Joule's heating effect?

Single Answer MCQ
Q-00019387
View explanation
Q250

What is the role of an ammeter in a circuit related to heating?

Single Answer MCQ
Q-00019388
View explanation
Q251

What is the SI unit of electric power?

Single Answer MCQ
Q-00019389
View explanation
Q252

If a device consumes 500 W of power for 10 hours, how much energy does it use in kilowatt-hours?

Single Answer MCQ
Q-00019390
View explanation
Q253

A light bulb operates at a power of 60 W. How much current does it draw if it is connected to a 120 V supply?

Single Answer MCQ
Q-00019391
View explanation
Q254

What is the relationship between power, voltage, and current?

Single Answer MCQ
Q-00019392
View explanation
Q255

An electric motor runs with a current of 10 A at a voltage of 230 V. What is the power consumed by the motor?

Single Answer MCQ
Q-00019393
View explanation
Q256

Which of the following statements about electrical energy is correct?

Single Answer MCQ
Q-00019394
View explanation
Q257

How much energy is consumed by a 100 W bulb in 5 hours?

Single Answer MCQ
Q-00019395
View explanation
Q258

If the resistance of a circuit is 5 ohms and the power consumed is 100 W, what is the voltage across the circuit?

Single Answer MCQ
Q-00019396
View explanation
Q259

Which of the following is a larger unit of electric power?

Single Answer MCQ
Q-00019397
View explanation
Q260

A device runs on 240 V, and if it consumes 2 kW of power, what is the current flowing through it?

Single Answer MCQ
Q-00019398
View explanation
Q261

What happens to the resistance of a conductor if the temperature increases?

Single Answer MCQ
Q-00019399
View explanation
Q262

What is the total energy consumption of a refrigerator rated at 150 W running for 24 hours?

Single Answer MCQ
Q-00019400
View explanation
Q263

In which unit is energy consumed by electrical appliances typically measured?

Single Answer MCQ
Q-00019401
View explanation
Q264

If a fuse wire melts due to high current, what does it indicate?

Single Answer MCQ
Q-00019402
View explanation
Q265

In an electric circuit, which term accurately describes the potential energy per charge?

Single Answer MCQ
Q-00019403
View explanation
Q266

What is defined as the flow of electric charge in a conductor?

Single Answer MCQ
Q-00040383
View explanation
Q267

What is the unit of electric current?

Single Answer MCQ
Q-00040384
View explanation
Q268

If 2 coulombs of charge pass through a cross-section in 4 seconds, what is the current?

Single Answer MCQ
Q-00040385
View explanation
Q269

Which statement best describes the function of a switch in an electric circuit?

Single Answer MCQ
Q-00040386
View explanation
Q270

What happens to the current in a circuit if the resistance increases, while the voltage remains constant?

Single Answer MCQ
Q-00040387
View explanation
Q271

Which of the following components is NOT typically used in a simple electric circuit?

Single Answer MCQ
Q-00040388
View explanation
Q272

How is the direction of conventional current defined?

Single Answer MCQ
Q-00040389
View explanation
Q273

What device is used to measure electric current in a circuit?

Single Answer MCQ
Q-00040390
View explanation
Q274

What is the total resistance in a series circuit with three resistors of 2 Ω, 3 Ω, and 5 Ω?

Single Answer MCQ
Q-00040391
View explanation
Q275

If a circuit has a potential difference of 12 volts and a resistance of 4 ohms, what is the current flowing through the circuit?

Single Answer MCQ
Q-00040392
View explanation
Q276

What is the charge of one electron?

Single Answer MCQ
Q-00040393
View explanation
Q277

What occurs in a circuit when the switch is open?

Single Answer MCQ
Q-00040394
View explanation
Q278

During which situation does electric current produce heat in a conductor?

Single Answer MCQ
Q-00040395
View explanation
Q279

What is the equivalent current in milliamperes (mA) for 0.02 A?

Single Answer MCQ
Q-00040396
View explanation
Q280

What is the role of a resistor in an electric circuit?

Single Answer MCQ
Q-00040397
View explanation
Q281

How many electrons are there in one coulomb of charge?

Single Answer MCQ
Q-00040398
View explanation
Q282

What is the SI unit of electric potential difference?

Single Answer MCQ
Q-00040399
View explanation
Q283

How is electric potential difference defined?

Single Answer MCQ
Q-00040400
View explanation
Q284

If a potential difference of 5 V moves a charge of 2 C, what is the work done?

Single Answer MCQ
Q-00040401
View explanation
Q285

What causes electric charges to flow in a conductor?

Single Answer MCQ
Q-00040402
View explanation
Q286

When is the potential difference across a cell zero?

Single Answer MCQ
Q-00040403
View explanation
Q287

What is the role of a voltmeter in a circuit?

Single Answer MCQ
Q-00040404
View explanation
Q288

A potential difference of 12 V is applied to a circuit. What energy is given to a charge of 3 C?

Single Answer MCQ
Q-00040405
View explanation
Q289

What is meant by potential difference being 1 V?

Single Answer MCQ
Q-00040406
View explanation
Q290

What happens to the potential difference in a closed circuit with a battery?

Single Answer MCQ
Q-00040407
View explanation
Q291

Which of the following is always connected in parallel?

Single Answer MCQ
Q-00040408
View explanation
Q292

If a battery generates a potential difference of 4.5 V, how much energy does it provide to 2 coulombs of charge?

Single Answer MCQ
Q-00040409
View explanation
Q293

As the resistance in a circuit increases while maintaining a constant voltage, what happens to the current?

Single Answer MCQ
Q-00040410
View explanation
Q294

Which of the following describes the flow of electric charges in a conductor?

Single Answer MCQ
Q-00040411
View explanation
Q295

What is the relationship between work done, potential difference, and charge?

Single Answer MCQ
Q-00040412
View explanation
Q296

What type of circuit would you use to ensure that all components receive the same voltage?

Single Answer MCQ
Q-00040413
View explanation
Q297

In a circuit with a potential difference and increased load, what must happen for the voltage to remain constant?

Single Answer MCQ
Q-00040414
View explanation
Q298

What does the symbol of an electric cell typically represent in a circuit diagram?

Single Answer MCQ
Q-00040415
View explanation
Q299

Which of the following symbols represents a closed switch in a circuit diagram?

Single Answer MCQ
Q-00040416
View explanation
Q300

In a circuit diagram, how is a battery represented?

Single Answer MCQ
Q-00040417
View explanation
Q301

Which factor directly affects the resistance of a conductor?

Single Answer MCQ
Q-00040418
View explanation
Q302

What does Ohm's Law state?

Single Answer MCQ
Q-00040419
View explanation
Q303

What is the purpose of a voltmeter in a circuit diagram?

Single Answer MCQ
Q-00040420
View explanation
Q304

If the length of a conductor is doubled, how does that affect its resistance?

Single Answer MCQ
Q-00040421
View explanation
Q305

Which component is essential for controlling current flow in a circuit?

Single Answer MCQ
Q-00040422
View explanation
Q306

A circuit has a voltage of 12 V and a resistance of 3 Ω. What is the current flowing through the circuit?

Single Answer MCQ
Q-00040423
View explanation
Q307

Which of the following statements is true about the area of cross-section and resistance?

Single Answer MCQ
Q-00040424
View explanation
Q308

If a circuit contains a resistor and it is represented by a zigzag line, what does it indicate?

Single Answer MCQ
Q-00040425
View explanation
Q309

If the resistance of a circuit is doubled while keeping the voltage constant, what happens to the current?

Single Answer MCQ
Q-00040426
View explanation
Q310

What happens to the resistance when using a thicker wire of the same length and material?

Single Answer MCQ
Q-00040427
View explanation
Q311

In a simple circuit represented in a diagram, which symbol indicates wires crossing without connecting?

Single Answer MCQ
Q-00040428
View explanation
Q312

A light bulb has a resistance of 60 Ω and operates at 120 V. What is the current flowing through the bulb?

Single Answer MCQ
Q-00040429
View explanation
Q313

Which material would likely exhibit the highest resistance?

Single Answer MCQ
Q-00040430
View explanation
Q314

How is a fuse represented in a circuit diagram?

Single Answer MCQ
Q-00040431
View explanation
Q315

If the voltage across a resistor is 10 V and the current is 2 A, what is the resistance?

Single Answer MCQ
Q-00040432
View explanation
Q316

According to Ohm's law, if voltage is constant and resistance increases, what happens to the current?

Single Answer MCQ
Q-00040433
View explanation
Q317

What is the function of an ammeter in a circuit represented in a diagram?

Single Answer MCQ
Q-00040435
View explanation
Q318

What would happen to the current in a circuit if the resistance increases while the voltage remains constant?

Single Answer MCQ
Q-00040434
View explanation
Q319

Which of the following is true about resistivity?

Single Answer MCQ
Q-00040436
View explanation
Q320

If one of the components in a series circuit fails, what happens to the rest of the circuit?

Single Answer MCQ
Q-00040437
View explanation
Q321

If a resistor has a resistance of 100 Ω and the current is increased to 3 A, what will be the new voltage across the resistor?

Single Answer MCQ
Q-00040438
View explanation
Q322

When a material is heated, what generally happens to its resistance?

Single Answer MCQ
Q-00040439
View explanation
Q323

Which is the typical arrangement of components in a parallel circuit diagram?

Single Answer MCQ
Q-00040440
View explanation
Q324

A circuit with a total resistance of 10 Ω has a total voltage of 50 V. What is the total current in the circuit?

Single Answer MCQ
Q-00040441
View explanation
Q325

Which formula represents the relationship between resistance, resistivity, length, and area?

Single Answer MCQ
Q-00040442
View explanation
Q326

In a circuit diagram, how is a variable resistor or rheostat represented?

Single Answer MCQ
Q-00040443
View explanation
Q327

What is the unit of resistance?

Single Answer MCQ
Q-00040444
View explanation
Q328

What effect does the material's resistivity have on the conductor's overall resistance?

Single Answer MCQ
Q-00040445
View explanation
Q329

What is the potential difference across a conductor if a 12 V battery is connected in a circuit?

Single Answer MCQ
Q-00040446
View explanation
Q330

In a circuit with two resistors in series of 4 Ω and 6 Ω, what would the total resistance be?

Single Answer MCQ
Q-00040447
View explanation
Q331

Which of the following statements about resistors is false?

Single Answer MCQ
Q-00040448
View explanation
Q332

Which circuit arrangement requires all components to be connected end-to-end?

Single Answer MCQ
Q-00040449
View explanation
Q333

If a 10 m wire with a resistance of 5 ohms is cut in half, what is the resistance of each half?

Single Answer MCQ
Q-00040450
View explanation
Q334

If a device has a current of 2 A at a voltage of 12 V, how much power does it consume?

Single Answer MCQ
Q-00040451
View explanation
Q335

In a circuit diagram with three resistors in parallel, how does the equivalent resistance compare to the individual resistances?

Single Answer MCQ
Q-00040452
View explanation
Q336

A wire has a length of 2 m and a cross-sectional area of 1 mm², resulting in a resistance of 5 Ω. If the wire is cut in half, what will be the new resistance?

Single Answer MCQ
Q-00040453
View explanation
Q337

When resistors are connected in series, how is total resistance calculated?

Single Answer MCQ
Q-00040454
View explanation
Q338

What happens to the total current in a parallel circuit if one branch is disconnected?

Single Answer MCQ
Q-00040455
View explanation
Q339

How does temperature affect the resistance of a conductor?

Single Answer MCQ
Q-00040456
View explanation
Q340

In practical applications, why are alloys preferred for resistors over pure metals?

Single Answer MCQ
Q-00040457
View explanation
Q341

Which of the following is NOT typically shown in a circuit diagram?

Single Answer MCQ
Q-00040458
View explanation
Q342

For a certain resistor, the voltage drop across it is 8 V, and it dissipates 32 W of power. What is the current through the resistor?

Single Answer MCQ
Q-00040459
View explanation
Q343

If two resistors of values 2 ohms and 3 ohms are connected in series, what is their equivalent resistance?

Single Answer MCQ
Q-00040460
View explanation
Q344

Why might a circuit breaker trip in a household circuit?

Single Answer MCQ
Q-00040461
View explanation
Q345

In an alternating current (AC) circuit, how does Ohm's Law still apply?

Single Answer MCQ
Q-00040462
View explanation
Q346

What happens to the temperature of a conductor when electric current flows through it?

Single Answer MCQ
Q-00040463
View explanation
Q347

The heating effect of current is primarily due to which phenomenon?

Single Answer MCQ
Q-00040464
View explanation
Q348

Which device uses the heating effect of electric current to function?

Single Answer MCQ
Q-00040465
View explanation
Q349

If a 220 V heater draws a current of 10 A, what is the power consumed by the heater?

Single Answer MCQ
Q-00040466
View explanation
Q350

How much heat is generated when a current of 5 A flows through a resistance of 10 Ω for 2 minutes?

Single Answer MCQ
Q-00040467
View explanation
Q351

What type of current produces heat when passing through a conductor?

Single Answer MCQ
Q-00040468
View explanation
Q352

A fuse is used in an electrical circuit primarily for what purpose?

Single Answer MCQ
Q-00040469
View explanation
Q353

When is the heating effect of current considered undesirable?

Single Answer MCQ
Q-00040470
View explanation
Q354

What metal is commonly used for filaments in light bulbs due to its high melting point?

Single Answer MCQ
Q-00040471
View explanation
Q355

What is the heat produced by passing 100 C of charge through a 20 V potential difference in 5 seconds?

Single Answer MCQ
Q-00040472
View explanation
Q356

Which of the following scenarios utilizes the heating effect of electric current?

Single Answer MCQ
Q-00040473
View explanation
Q357

What does the power rating of an appliance indicate?

Single Answer MCQ
Q-00040474
View explanation
Q358

In electrical heating, what is Joule's law primarily concerned with?

Single Answer MCQ
Q-00040475
View explanation
Q359

What is the unit of power in an electrical system?

Single Answer MCQ
Q-00040476
View explanation
Q360

How is the heat generated in a resistor affected by increasing the current?

Single Answer MCQ
Q-00040477
View explanation
Q361

What is the equivalent resistance of two resistors, R1 = 4 Ω and R2 = 6 Ω, connected in series?

Single Answer MCQ
Q-00040478
View explanation
Q362

When resistors are connected in parallel, how does the equivalent resistance compare to the smallest resistor?

Single Answer MCQ
Q-00040479
View explanation
Q363

If three resistors of values 2 Ω, 4 Ω, and 6 Ω are connected in parallel, what is the equivalent resistance?

Single Answer MCQ
Q-00040480
View explanation
Q364

What will happen to the total resistance when more resistors are added in series?

Single Answer MCQ
Q-00040481
View explanation
Q365

What is the current through a 10 Ω resistor if the voltage across it is 50 V?

Single Answer MCQ
Q-00040482
View explanation
Q366

Which connection results in greater total current from the voltage source: series or parallel?

Single Answer MCQ
Q-00040483
View explanation
Q367

Calculate the equivalent resistance of a circuit with a 4 Ω and a 12 Ω resistor connected in parallel.

Single Answer MCQ
Q-00040484
View explanation
Q368

What happens to the current in a circuit when total resistance increases while the voltage remains constant?

Single Answer MCQ
Q-00040485
View explanation
Q369

If two resistors, 5 Ω and 15 Ω, are connected in series and the voltage across them is 60 V, what is the voltage across the 5 Ω resistor?

Single Answer MCQ
Q-00040486
View explanation
Q370

How can you achieve the lowest equivalent resistance with four resistors of 10 Ω each?

Single Answer MCQ
Q-00040487
View explanation
Q371

What is the result of connecting three resistors of 3 Ω, 6 Ω, and 9 Ω in series?

Single Answer MCQ
Q-00040488
View explanation
Q372

In a parallel arrangement of resistors, if one resistor fails, what happens to the total circuit?

Single Answer MCQ
Q-00040489
View explanation
Q373

If the equivalent resistance of three resistors in series is 30 Ω and the resistors are 5 Ω, 10 Ω, and R3, what is R3?

Single Answer MCQ
Q-00040490
View explanation
Q374

Which properties change when resistors are connected in parallel?

Single Answer MCQ
Q-00040491
View explanation
Q375

If the power supplied to a resistor is 200 W at a voltage of 100 V, what is the resistance?

Single Answer MCQ
Q-00040492
View explanation
Q376

The resistance of a wire of 0.01 cm radius and 1.0 cm length is 7 Ω. Calculate its resistivity in Ω m.

Number
Q-00205875
View explanation
Q377

An electric heater is rated 220 V; 11 A. Calculate the power consumed if the heater is operated at 200 V.

Number
Q-00205877
View explanation
Q378

Consider the given electric circuit. Calculate the total electric current drawn from the source.

Number
Q-00205889
View explanation
Q379

Consider the given electric circuit. Calculate the total resistance of the circuit.

Number
Q-00205891
View explanation
Q380

Consider the given electric circuit. Calculate the potential difference across 3 Ω resistor.

Number
Q-00205890
View explanation
Q381

Two bulbs, rated as 100 W; 220 V and 60 W; 220 V are connected in parallel to an electric main supply of 220 V. Calculate the electric current drawn from the mains.

Number
Q-00205892
View explanation
Q382

State Ohm’s law and draw V-I graph for a conductor which follows Ohm’s law. Show that the slope of V-I graph gives resistance of conductor.

Text
Q-00205893
View explanation
Q383

Derive an expression for the equivalent resistance of a series combination of three resistors having resistances R1, R2 and R3.

Text
Q-00205894
View explanation
Q384

The resistance of a wire of 0.01 cm radius and 1.0 cm length is 7 Ω. Calculate its resistivity.

Number
Q-00205962
View explanation
Q385

An electric heater is rated 220 V; 11 A. Calculate the power consumed if this heater is operated at 200 V.

Number
Q-00205963
View explanation
Q386

Study the given electric circuit, in which 2 A electric current is flowing between points X and Y. Using the battery, key, voltmeter and ammeter in this given electric circuit, redraw a circuit diagram in which 2 Ω and 4 Ω resistors are connected between X and Y in parallel combination.

Text
Q-00205974
View explanation
Q387

Study the electric circuit redrawn with 2 Ω and 4 Ω resistors connected in parallel. Calculate the electric current flowing through 4 Ω resistor.

Text
Q-00205976
View explanation
Q388

Two lamps ‘A’ and ‘B’ of rating 50 W; 220 V and 100 W; 220 V are connected in series combination. Find out the ratio of the resistances (RA : RB) of these lamps.

Text
Q-00205977
View explanation
Q389

Derive the expression for the equivalent resistance of three resistors R1, R2 and R3 connected in parallel combination.

Text
Q-00205978
View explanation
Q390

The values of current I flowing in a resistor and corresponding potential difference V are: I (A): 0.4, 0.8, 1.2, 1.6, 2.0; V (V): 1.2, 2.4, 3.6, 4.8, 6.0. Plot a graph between V and I and calculate the resistance of that resistor.

Text
Q-00206044
View explanation
Q391

Swati observes heat near a refrigerator although things inside are cool. Describe the cause of heating in this case.

Text
Q-00206045
View explanation
Q392

A current I flows through a resistor of resistance R when potential difference V is applied. Applying Ohm's law, write the formula for amount of heat produced by the resistor in time t.

Text
Q-00206046
View explanation
Q393

Define the commercial unit of electric energy and express it in Joules (J).

Text
Q-00206047
View explanation
Q394

Write any two practical applications of heating effect of electric current.

Text
Q-00206048
View explanation
Q395

The values of current I flowing in a given resistor for the corresponding values of potential difference V applied across the ends of resistor are given: I (A): 0.4, 0.8, 1.2, 1.6, 2.0; V (V): 1.2, 2.4, 3.6, 4.8, 6.0. Plot a graph between V and I and calculate the resistance of that resistor.

Text
Q-00206124
View explanation
Q396

Swati observes that when she passes close to the refrigerator in her kitchen, she feels heat, although the things kept inside the refrigerator are cool. Describe the cause of heating in the above-mentioned case.

Text
Q-00206127
View explanation
Q397

A current I flows through a resistor of resistance R when the potential difference across it is V. Applying Ohm’s law, write the formula for amount of heat produced by the resistor in time t.

Text
Q-00206128
View explanation
Q398

Write any two practical applications of heating effect of electric current.

Text
Q-00206129
View explanation
Q399

Define the commercial unit of electric energy and express it in Joules (J).

Text
Q-00206130
View explanation
Q400

The values of current I flowing in a given resistor for the corresponding values of potential difference V applied across the ends of resistor are given below: I (A): 0.4, 0.8, 1.2, 1.6, 2.0; V (V): 1.2, 2.4, 3.6, 4.8, 6.0. Plot a graph between V and I and calculate the resistance of that resistor.

Text
Q-00206266
View explanation
Q401

Swati observes that when she passes close to the refrigerator in her kitchen, she feels heat, although the things kept inside the refrigerator are cool. Describe the cause of heating in the above-mentioned case.

Text
Q-00206267
View explanation
Q402

A current I flows through a resistor of resistance R when the potential difference across it is V. Applying Ohm’s law, write the formula for amount of heat produced by the resistor in time t.

Text
Q-00206268
View explanation
Q403

Write any two practical applications of heating effect of electric current.

Text
Q-00206270
View explanation
Q404

Define the commercial unit of electric energy and express it in Joules (J).

Text
Q-00206272
View explanation
Q405

Draw a schematic diagram of a domestic electric circuit which includes the following devices: a fuse, a power meter, one light point and a power plug.

Text
Q-00206275
View explanation
Q406

Why is it necessary to connect an earth wire to the electrical appliances having metallic covers?

Text
Q-00206277
View explanation
Q407

The correct way to connect an ammeter and a voltmeter in an electric circuit is:

Single Answer MCQ
Q-00206339
View explanation
Q408

Name a device which is used to maintain a constant potential difference in a circuit.

Text
Q-00206348
View explanation
Q409

Name a device which is used to change the electric current in an electric circuit.

Text
Q-00206349
View explanation
Q410

When the potential difference between the terminals of an electric heater is 110 V, a current of 5 A flows through it. What will be the value of current flowing through it when the potential difference is increased to 220 V?

Number
Q-00206350
View explanation
Q411

Consider the given electric circuit. Calculate the total resistance of the circuit.

Number
Q-00206351
View explanation
Q412

Consider the given electric circuit. Calculate the electric current drawn from the battery.

Number
Q-00206352
View explanation
Q413

Consider the given electric circuit. Calculate the potential difference between points P and Q.

Number
Q-00206353
View explanation
Q414

The resistance of a wire of 0.01 cm radius and 1.0 cm length is 7 Ω. Calculate its resistivity.

Number
Q-00206430
View explanation
Q415

An electric heater is rated 220 V; 11 A. Calculate the power consumed if the heater is operated at 200 V.

Number
Q-00206431
View explanation
Q416

Due to change in length and area of cross-section of a conductor, resistance of conductor changes while resistivity does not change. Why?

Text
Q-00206441
View explanation
Q417

Define the S.I. unit of electric current.

Text
Q-00206442
View explanation
Q418

Conductors of electric toasters and electric iron are made of an alloy rather than a pure metal. Why?

Text
Q-00206443
View explanation
Q419

How many bulbs of resistance 8 Ω each should be connected in parallel combination to draw a current of 2 A from a battery of 4 V?

Number
Q-00206444
View explanation
Q420

State Joule’s law of heating.

Text
Q-00206445
View explanation
Q421

Name the device used for measuring electric current. How is it connected in a circuit?

Text
Q-00206446
View explanation
Q422

The correct way to connect an ammeter and a voltmeter in an electric circuit is:

Single Answer MCQ
Q-00206508
View explanation
Q423

Consider the given electric circuit. Calculate the total resistance of the circuit.

Number
Q-00206515
View explanation
Q424

Consider the given electric circuit. Calculate the electric current drawn from the battery.

Number
Q-00206517
View explanation
Q425

Consider the given electric circuit. Calculate the potential difference between points P and Q.

Number
Q-00206516
View explanation
Q426

State Ohm’s law and justify that V-I graph for Ohm’s law will always be a straight line passing through the origin.

Text
Q-00206521
View explanation
Q427

The figure shows V-I graphs for two identical wires A and B having the same length and area of cross-section, but made of different materials. Which of these wires will be more suitable for making the heating element of an electric heater and why?

Text
Q-00206522
View explanation
Q428

What is the value of standard potential difference at which electricity is supplied in Indian homes for lighting?

Number
Q-00206527
View explanation
Q429

What is the role of earthing in domestic electric circuits?

Text
Q-00206529
View explanation
Q430

What is the role of fuse in domestic electric circuits?

Text
Q-00206528
View explanation
Q431

A person repairing an electric heater observed three different connecting wires of three different colours in the cable attached to the heater. What are these three different wires called? Name them colourwise.

Text
Q-00206534
View explanation
Q432

Work done in displacing an electron between two points having potential difference of 1 V, is:

Single Answer MCQ
Q-00206587
View explanation
Q433

State the role of fuse and earthing in domestic electric circuit. Suggest any two precautions to be taken to avoid electrical accidents.

Text
Q-00206596
View explanation
Q434

In a house, 5 fans, rated 100 W; 220 V each are used for 4 hours daily and an electric heater rated 1000 W; 220 V is used for 5 hours daily. Calculate the cost of electrical energy consumed by the fans and the electric heater in a month of 30 days if the cost of 1 unit of electrical energy is ₹ 5.

Number
Q-00206602
View explanation
Q435

You have two fuse wires X and Y with electric current rating 5 A and 10 A respectively. Which of the two would you use with a heater rated 2000 W; 220 V? Justify your answer.

Text
Q-00206601
View explanation
Q436

State the relationship of the resistance (R) of a wire with its area of cross-section (A) and its length (l). With the help of this relation, define resistivity of the material of the wire.

Text
Q-00206604
View explanation
Q437

In an electric circuit, 2 A electric current flows through a 40 Ω resistor for 50 seconds. (I) Calculate the heat produced in the wire. (II) If another 40 Ω resistor is connected in parallel to the given 40 Ω resistor, calculate the heat produced in the circuit in 50 seconds.

Number
Q-00206603
View explanation
Q438

A fuse in an electric circuit is rated 4 A. Can it be used with an electric heater of rating 2 kW, 200 V? Explain your answer.

Text
Q-00206664
View explanation
Q439

Define volt, the unit of potential difference.

Text
Q-00206667
View explanation
Q440

Calculate the work done required to move an electron between two points A and B located at a potential difference of 100 V in an electric field.

Text
Q-00206669
View explanation
Q441

Using the given electric circuit diagram, calculate the potential difference across the ends of resistor R2.

Text
Q-00206679
View explanation
Q442

Using the given electric circuit diagram, calculate the value of resistor R2.

Text
Q-00206680
View explanation
Q443

Using the given electric circuit diagram, calculate the value of resistor R1.

Text
Q-00206681
View explanation
Q444

How much electric current will an electric iron draw from a 220 V source if the resistance of its heating element when hot is 55 Ω? Calculate the power consumed when operated at 220 V.

Text
Q-00206682
View explanation
Q445

Write the factors on which resistance of a conductor depends and derive the formula for resistance of a given conductor.

Text
Q-00206683
View explanation
Q446

In a house, 3 bulbs of 100 W each are lit for 5 hours daily and a 1.0 kW electric heater is used for half an hour daily. Calculate total energy consumed in 30 days and its cost at ₹3.60 per kWh.

Text
Q-00206684
View explanation
Q447

With reason explain why alloys are commonly used to make elements of electrical heating devices.

Text
Q-00206685
View explanation
Q448

A fuse in electric circuit is rated 4 A. Can it be used with an electric heater of rating 2 kW, 200 V? Explain your answer.

Text
Q-00206749
View explanation
Q449

What does the given symbol (circle marked V connected across two terminals, with + and − signs) represent in an electric circuit? Write one function.

Text
Q-00206751
View explanation
Q450

What does the given symbol (zig-zag resistor with an arrow touching it) represent in an electric circuit? Write one function.

Text
Q-00206752
View explanation
Q451

V-I graph for a nichrome wire is shown in the diagram. Prove that the graph follows Ohm’s law and calculate the resistance of nichrome wire from the given V-I graph.

Text
Q-00206764
View explanation
Q452

Calculate the equivalent resistance of the combination of resistors connected in the given circuit.

Text
Q-00206765
View explanation
Q453

Define the SI unit of power. Express the electric power of an electric appliance in terms of potential difference and current flowing through it.

Text
Q-00206766
View explanation
Q454

Find the value of the total current drawn from the battery in the given circuit.

Text
Q-00206767
View explanation
Q455

In a house, 3 bulbs of 100 W each are lit for 5 hours daily and an electric heater of 1.0 kW is used for half an hour daily. Calculate the total energy consumed in a month of 30 days and its cost at the rate of ₹ 3.60 per kWh.

Text
Q-00206768
View explanation
Q456

Convert the commercial unit of electric energy into Joule (J).

Text
Q-00206769
View explanation
Q457

A fuse in electric circuit is rated 4 A. Can it be used with an electric heater of rating 2 kW, 200 V? Explain your answer.

Text
Q-00206833
View explanation
Q458

State the law which gives the relation between the electric current flowing through a given conductor and the potential difference applied across it.

Text
Q-00206835
View explanation
Q459

Draw V-I graph for a given conductor as per the law stated in question 34(a).

Text
Q-00206836
View explanation
Q460

Derive an expression for the equivalent resistance of three resistors connected in parallel with a battery as shown in figure.

Essay
Q-00206845
View explanation
Q461

Find the values of the electric currents flowing through the resistors R1, R2 and R3 in the given electric circuit.

Text
Q-00206846
View explanation
Q462

Define electrical resistivity of a material.

Text
Q-00206847
View explanation
Q463

How will the resistivity and resistance of a conducting wire change if the length and area of cross-section of wire both are doubled? Justify your answer.

Text
Q-00206849
View explanation
Q464

Calculate the electric current flowing through a 4 Ω resistor that produces 100 J of heat every second.

Number
Q-00206850
View explanation
Q465

Why does an electric bulb become dim when an electric heater in parallel circuit is switched ON?

Text
Q-00206906
View explanation
Q466

Three students Shweta, Ayesha and Samridhi were performing an experiment to understand the factors on which the resistance of a conductor depends. Each one of them completed electric circuit with the help of a cell, an ammeter, a plug key and wire. Shweta put nichrome wire of length ‘l’ in the circuit and after plugging the key, noted current in the ammeter. Ayesha put nichrome wire of same thickness but twice the length i.e. ‘2l’ in the circuit and after plugging the key, noted current in the ammeter. Samridhi took copper wire of length ‘l’ and same thickness in the circuit and after plugging the key, noted current in the ammeter. If the ammeter reading is X ampere with nichrome wire of length ‘l’, then what will be the ammeter reading if the length of nichrome wire is doubled with same area of cross-section?

Text
Q-00206907
View explanation
Q467

How to connect three resistors each of resistance 8 Ω, so that the equivalent resistance of the combination is 12 Ω? Draw diagram of the combination and justify your answer.

Text
Q-00206908
View explanation
Q468

What happens to the ammeter reading if the area of cross-section of nichrome wire is doubled, keeping the length of wire ‘l’ the same?

Text
Q-00206909
View explanation
Q469

Define ‘resistivity’. Write its SI unit. Compare the resistivity of an alloy with its constituents metals.

Text
Q-00206910
View explanation
Q470

Give reason: (i) Tungsten is used almost exclusively for making the filament of electric lamps. (ii) Conductors of bread-toasters are made of an alloy rather than a pure metal.

Text
Q-00206911
View explanation
Q471

In an electric circuit carrying current I, a 2 ohm resistor is replaced by an 8 ohm resistor without changing the connected ideal battery. Then:

Single Answer MCQ
Q-00206953
View explanation
Q472

Name a device used to maintain a constant potential difference in a circuit.

Text
Q-00206958
View explanation
Q473

Name a device used to change the electric current in an electric circuit.

Text
Q-00206960
View explanation
Q474

Calculate the total resistance of the given electric circuit.

Number
Q-00206961
View explanation
Q475

When the potential difference between the terminals of an electric heater is 110 V, a current of 5 A flows through it. What current will flow when the potential difference is increased to 220 V?

Number
Q-00206962
View explanation
Q476

Calculate the electric current drawn from the 10 V battery in the given circuit.

Number
Q-00206963
View explanation
Q477

Calculate the potential difference between points P and Q in the given circuit.

Number
Q-00206964
View explanation
Q478

Why does an electric bulb become dim when an electric heater in parallel circuit is switched ON?

Text
Q-00207048
View explanation
Q479

How to connect three resistors each of resistance 8 Ω, so that the equivalent resistance of the combination is 12 Ω? Draw diagram of the combination and justify your answer.

Text
Q-00207050
View explanation
Q480

If the ammeter reading is X ampere with nichrome wire of length ‘l’, what will be the ammeter reading if the length of nichrome wire is doubled with same area of cross-section?

Text
Q-00207054
View explanation
Q481

Define ‘resistivity’. Write its SI unit. Compare the resistivity of an alloy with its constituent metals.

Text
Q-00207056
View explanation
Q482

What happens to the ammeter reading if the area of cross-section of nichrome wire is doubled, keeping the length of wire ‘l’ the same?

Text
Q-00207057
View explanation
Q483

Give reason: Tungsten is used almost exclusively for making the filament of electric lamps.

Text
Q-00207055
View explanation
Q484

Give reason: Conductors of bread-toasters are made of an alloy rather than a pure metal.

Text
Q-00207060
View explanation
Q485

Why does an electric bulb become dim when an electric heater in parallel circuit is switched ON ?

Text
Q-00207143
View explanation
Q486

How can three resistors each of resistance 8 ohm be connected so that the equivalent resistance is 12 ohm ? Draw the combination and justify.

Text
Q-00207144
View explanation
Q487

What happens to the ammeter reading if the area of cross-section of nichrome wire is doubled, keeping the length l the same ?

Text
Q-00207145
View explanation
Q488

If the ammeter reading is X ampere with nichrome wire of length l, what will be the ammeter reading if the length of nichrome wire is doubled with the same area of cross-section ?

Text
Q-00207146
View explanation
Q489

Define resistivity. Write its SI unit. Compare the resistivity of an alloy with its constituent metals.

Text
Q-00207147
View explanation
Q490

Give reason: Tungsten is used almost exclusively for making the filament of electric lamps.

Text
Q-00207148
View explanation
Q491

Give reason: Conductors of bread-toasters are made of an alloy rather than a pure metal.

Text
Q-00207150
View explanation
Q492

In case of overload, will the fuse protect the given electric circuit from damage ? Justify your answer.

Text
Q-00207153
View explanation
Q493

List three possible reasons of short-circuiting in an electric circuit.

Text
Q-00207155
View explanation
Q494

For an electric heater rated as 220 V, 2200 W, what should be the minimum rating of fuse used with it ?

Text
Q-00207154
View explanation
Q495

Four wires a, b, c and d are made of the same materials. If ‘l’ denotes length and ‘r’ denotes radius, then the wire which offers least resistance to the flow of electric current has length and radius respectively as:

Single Answer MCQ
Q-00209016
View explanation

Electricity Practice Worksheets

Download and practice Electricity worksheets to improve problem-solving accuracy and speed for CBSE Class 10 Science exams.

Electricity - Practice Worksheet

This worksheet covers essential long-answer questions to help you build confidence in Electricity from Science for Class X (Science).

Practice

Questions

1

What is electric current and how is it measured?

Electric current is the flow of electric charge through a conductor. It is measured as the rate of flow of charge, where the SI unit is the ampere (A). The formula to calculate current is I = Q/t, where I is the current, Q is the charge in coulombs, and t is the time in seconds. For example, if a charge of 5 coulombs flows through a conductor in 2 seconds, the current is 2.5 A. Electric current is measured using an ammeter, which is connected in series in the circuit. The direction of conventional current is opposite to the flow of electrons. In real life, electric current powers devices like bulbs and heaters by allowing electrons to flow through them, providing energy for operation.

2

Explain Ohm's Law and its significance in electric circuits.

Ohm's Law states that the current through a conductor between two points is directly proportional to the voltage across the two points, provided the temperature remains constant. Mathematically, it is expressed as V = IR, where V is the voltage, I is the current, and R is the resistance. This law is fundamental in designing and analyzing electric circuits because it helps in calculating the current, voltage, or resistance when the other two quantities are known. For example, if a resistor of 10 ohms has a voltage of 20 volts across it, the current through it is 2 amperes. Ohm's Law is crucial for understanding how different components in a circuit interact and is widely used in household and industrial electrical systems.

3

Describe the factors affecting the resistance of a conductor.

The resistance of a conductor depends on several factors: 1) Length - Resistance is directly proportional to the length of the conductor. Longer conductors have higher resistance. 2) Cross-sectional area - Resistance is inversely proportional to the cross-sectional area. Thicker wires have lower resistance. 3) Material - Different materials have different resistivities, affecting resistance. For example, copper has lower resistivity than iron. 4) Temperature - For most conductors, resistance increases with temperature. For example, the resistance of a tungsten filament increases as it heats up. Understanding these factors helps in selecting appropriate materials and dimensions for wires in electrical circuits to minimize energy loss and ensure efficient operation.

4

What is the difference between series and parallel connections of resistors?

In a series connection, resistors are connected end-to-end, and the same current flows through each resistor. The total resistance is the sum of individual resistances (R_total = R1 + R2 + R3). For example, three resistors of 2Ω, 3Ω, and 5Ω in series give a total resistance of 10Ω. In a parallel connection, resistors are connected across the same voltage, and the current divides among them. The total resistance is given by 1/R_total = 1/R1 + 1/R2 + 1/R3. For example, two resistors of 4Ω and 4Ω in parallel give a total resistance of 2Ω. Series connections are used where a single path for current is needed, while parallel connections are used to provide multiple paths, ensuring that if one path fails, others continue to work.

5

Explain the heating effect of electric current and its applications.

The heating effect of electric current occurs when electrical energy is converted into heat energy as current flows through a resistor. This is described by Joule's Law: H = I²Rt, where H is the heat produced, I is the current, R is the resistance, and t is the time. Practical applications include electric heaters, toasters, and incandescent bulbs, where the heating effect is utilized to produce warmth or light. For example, an electric iron uses a heating element with high resistance to generate heat for pressing clothes. Safety devices like fuses also rely on the heating effect to melt and break the circuit during overcurrent, preventing damage to appliances. While useful, the heating effect can also lead to energy loss in transmission lines, which is why high-voltage transmission is preferred to reduce current and thus heat loss.

6

What is electric power and how is it calculated?

Electric power is the rate at which electrical energy is consumed or transferred in a circuit. It is calculated using the formula P = VI, where P is power in watts (W), V is voltage in volts (V), and I is current in amperes (A). Other forms of the formula include P = I²R and P = V²/R, derived from Ohm's Law. For example, a device operating at 220V with a current of 5A consumes 1100W of power. The commercial unit of electrical energy is the kilowatt-hour (kWh), which represents the energy consumed by a 1kW device in one hour. Understanding electric power is essential for designing efficient electrical systems and calculating energy consumption for billing and conservation purposes.

7

Describe the role of a fuse in an electric circuit.

A fuse is a safety device that protects electrical circuits from overcurrent by melting and breaking the circuit when the current exceeds a safe value. It consists of a thin wire made of a material with a low melting point, such as tin or lead. When excessive current flows, the wire heats up and melts, interrupting the circuit and preventing damage to connected devices. Fuses are rated by their current capacity (e.g., 5A, 10A) and are selected based on the normal operating current of the circuit. For example, a 5A fuse is suitable for a circuit that normally carries 4A. Fuses are crucial in preventing fires and equipment damage caused by short circuits or overloads, making them an essential component in household and industrial electrical systems.

8

What is the difference between conductors and insulators?

Conductors are materials that allow electric current to flow easily due to the presence of free electrons, such as metals like copper and aluminum. They have low resistivity and are used in wires and cables to transmit electricity. Insulators, on the other hand, resist the flow of electric current because they have very few free electrons. Examples include rubber, glass, and plastic, which are used to coat wires and prevent accidental contact with live parts. The key difference lies in their electrical resistivity: conductors have resistivity in the range of 10^-8 to 10^-6 Ωm, while insulators have resistivity from 10^12 to 10^17 Ωm. This distinction is vital in designing electrical systems to ensure safe and efficient current flow where needed and insulation where necessary.

9

Explain how an electric bulb works and why tungsten is used for the filament.

An electric bulb works by passing current through a thin filament, which heats up to a high temperature and emits light due to incandescence. Tungsten is used for the filament because it has a high melting point (3380°C), allowing it to remain solid at the high temperatures required for light emission. Additionally, tungsten has high resistivity, which helps in generating sufficient heat. The filament is enclosed in a glass bulb filled with inert gases like argon or nitrogen to prevent oxidation and prolong its life. When current flows through the filament, electrical energy is converted into heat and light. However, most of the energy is lost as heat, making incandescent bulbs less efficient compared to modern alternatives like LEDs, which convert more energy into light.

10

Calculate the resistance of a wire if its length is doubled and its diameter is halved, given the original resistance.

The resistance of a wire is given by R = ρL/A, where ρ is resistivity, L is length, and A is cross-sectional area. If the length is doubled, resistance becomes 2R (since R ∝ L). If the diameter is halved, the area becomes A/4 (since A = πr² and r is halved). Thus, resistance becomes 8R (since R ∝ 1/A). Combining both changes, the new resistance is 2 * 8 = 16 times the original resistance. For example, if the original resistance was 5Ω, the new resistance would be 80Ω. This demonstrates how significantly changes in dimensions can affect resistance, which is important in designing electrical components to meet specific requirements.

Electricity - Mastery Worksheet

This worksheet challenges you with deeper, multi-concept long-answer questions from Electricity to prepare for higher-weightage questions in Class X Science.

Mastery

Questions

1

Explain the concept of electric current and how it is measured. Include the role of an ammeter in a circuit.

Electric current is the flow of electric charge through a conductor. It is measured as the rate of flow of charge, quantified by the equation I = Q/t, where I is the current, Q is the charge, and t is time. The SI unit of current is ampere (A). An ammeter is used to measure the current in a circuit and is always connected in series to ensure the same current flows through it as through the rest of the circuit.

2

Compare and contrast series and parallel connections of resistors with respect to current flow and potential difference.

In series connections, the same current flows through all resistors, and the total potential difference is the sum of individual potential differences across each resistor. The total resistance is the sum of individual resistances. In parallel connections, the potential difference across each resistor is the same, and the total current is the sum of currents through each resistor. The reciprocal of the total resistance is the sum of the reciprocals of individual resistances.

3

Describe the heating effect of electric current and derive the expression for heat produced in a resistor.

The heating effect of electric current is the phenomenon where electrical energy is converted into heat energy when current passes through a resistor. The heat produced (H) can be derived using Joule's law: H = I²Rt, where I is the current, R is the resistance, and t is the time. This shows that heat is directly proportional to the square of the current, the resistance, and the time.

4

Explain why tungsten is used as the filament in electric bulbs and how the bulb's design minimizes heat loss.

Tungsten is used because it has a high melting point (3380°C) and can withstand the high temperatures needed to emit light. The bulb is filled with inert gases like nitrogen and argon to prevent oxidation of the filament. The design includes a vacuum or gas filling to reduce heat loss through convection and conduction, and the filament is coiled to increase resistance and thus the heat and light produced.

5

Calculate the resistance of a wire given its length, cross-sectional area, and resistivity. How does resistance change if the wire's diameter is doubled?

The resistance (R) of a wire is given by R = ρl/A, where ρ is resistivity, l is length, and A is cross-sectional area. If the diameter is doubled, the area becomes four times larger (since A = πr²), and thus the resistance becomes one-fourth of its original value.

6

Discuss the factors affecting the resistance of a conductor and how they are related mathematically.

The resistance of a conductor depends on its length (l), cross-sectional area (A), and the material's resistivity (ρ). The relationship is given by R = ρl/A. Resistance increases with length and resistivity but decreases with an increase in cross-sectional area.

7

Explain the role of a fuse in an electric circuit and why it is important for safety.

A fuse is a safety device that protects electrical circuits from overcurrent. It contains a wire that melts when the current exceeds a certain value, breaking the circuit and preventing damage to appliances or fire hazards. Fuses are rated based on the maximum current they can handle safely.

8

Derive the expression for electric power in terms of current and resistance, and explain its significance.

Electric power (P) is the rate at which electrical energy is consumed. It can be expressed as P = VI. Using Ohm's law (V = IR), it can also be written as P = I²R or P = V²/R. This shows that power depends on the square of the current or voltage and is directly proportional to resistance in the first form and inversely in the second.

9

Compare the power consumption of two electric bulbs rated at 100 W and 60 W when connected to a 220 V supply. Which one draws more current and why?

The 100 W bulb draws more current because power (P) is directly proportional to current (I) for a given voltage (P = VI). Using I = P/V, the 100 W bulb has I = 100/220 ≈ 0.45 A, and the 60 W bulb has I = 60/220 ≈ 0.27 A. Thus, the higher power rating indicates higher current draw.

10

Explain the commercial unit of electrical energy and calculate the cost of operating a 400 W refrigerator for 30 days at Rs 3.00 per unit.

The commercial unit of electrical energy is the kilowatt-hour (kWh). To calculate the cost: Energy consumed = Power × Time = 400 W × 8 hours/day × 30 days = 96 kWh. Cost = 96 kWh × Rs 3.00/kWh = Rs 288.00.

Electricity - Challenge Worksheet

The final worksheet presents challenging long-answer questions that test your depth of understanding and exam-readiness for Electricity in Class X.

Challenge

Questions

1

Explain how the resistance of a conductor varies with its temperature and discuss its implications in real-life electrical devices.

The resistance of a conductor generally increases with temperature due to the increased vibration of atoms, which impedes the flow of electrons. This phenomenon is crucial in devices like incandescent bulbs, where the filament's resistance increases as it heats up, affecting its brightness and efficiency. However, in semiconductors, resistance decreases with temperature, showcasing the material-dependent nature of this relationship.

2

Analyze the advantages and disadvantages of connecting electrical appliances in parallel in domestic circuits.

Parallel connections allow each appliance to operate independently at the same voltage, ensuring that if one fails, others continue to work. This setup also enables the drawing of higher currents as needed. However, it requires more wiring and can lead to higher energy consumption if not managed properly, as each appliance draws current based on its resistance.

3

Derive the expression for the equivalent resistance of three resistors connected in parallel and discuss how this configuration affects the total current in the circuit.

The equivalent resistance (R_p) for three resistors (R1, R2, R3) in parallel is given by 1/R_p = 1/R1 + 1/R2 + 1/R3. This configuration decreases the total resistance, allowing a higher total current to flow through the circuit compared to a series connection, as the current has multiple paths to take, reducing the overall resistance to flow.

4

Evaluate the impact of wire thickness and length on the resistance and power loss in electrical transmission lines.

Thicker wires have lower resistance due to a larger cross-sectional area, reducing power loss (P = I²R) over long distances. Longer wires increase resistance, leading to higher power loss. Thus, for efficient power transmission, thicker and shorter wires are preferred, but practical constraints like cost and space must be considered.

5

Discuss the role of fuses in electrical circuits and how selecting an appropriate fuse rating is critical for safety.

Fuses protect circuits by melting and breaking the circuit when current exceeds a safe level, preventing damage or fire. Selecting a fuse with a rating slightly higher than the normal operating current ensures it doesn't blow during regular use but protects against surges. Incorrect ratings can lead to either frequent disruptions or failure to protect.

6

Compare the heating effects of electric current in series and parallel circuits with identical resistors and power supply.

In series, the same current flows through all resistors, leading to uniform heating proportional to each resistor's resistance. In parallel, the current divides, with more current flowing through lower resistance paths, causing uneven heating. Total power dissipation is higher in parallel due to lower equivalent resistance, leading to more total heat generated.

7

Explain why tungsten is used almost exclusively for the filaments of electric lamps, considering its properties.

Tungsten has a high melting point (3380°C) and high resistivity, making it ideal for filaments that must reach high temperatures to emit light without melting. Its ability to retain strength at high temperatures and low vapor pressure also prolongs the bulb's life, despite the higher cost compared to other materials.

8

Calculate the energy consumed by a 2 kW electric heater in 2 hours and express it in joules and kilowatt-hours. Discuss the significance of these units.

Energy = Power × Time = 2 kW × 2 h = 4 kWh. In joules, 4 kWh = 4 × 3.6 × 10^6 J = 14.4 × 10^6 J. kWh is practical for billing as it represents large energy quantities, while joules are fundamental units useful in scientific calculations, linking electrical energy to other forms of energy.

9

Investigate the consequences of using a wire with insufficient diameter in an electrical circuit intended for high current applications.

Using a wire with insufficient diameter increases its resistance, leading to excessive heat generation (P = I²R) and potential melting or fire. It also causes significant voltage drops across the wire, reducing the efficiency and performance of connected devices, and may trip circuit breakers or blow fuses due to overcurrent.

10

Design a circuit that includes a combination of series and parallel resistors to achieve a specific equivalent resistance, explaining your design choices.

To achieve a desired equivalent resistance, combine resistors in series to add their resistances (R_total = R1 + R2) or in parallel to reduce it (1/R_total = 1/R1 + 1/R2). For example, to get 4Ω from 6Ω resistors, connect two in parallel (1/R_total = 1/6 + 1/6 → R_total = 3Ω) and then add another in series (3Ω + 6Ω = 9Ω isn't desired, so adjust combinations). The exact configuration depends on available resistors and the target resistance, requiring iterative testing or algebraic solving.

Electricity Formula Sheet

Use this Class 10 Science Electricity Formula Sheet for quick revision before school exams and CBSE exams. It brings together the important formulas, key concepts, and worked examples in one place so students can revise faster and download a printable PDF for offline study.

Important Formulas

1

I = Q/t

I represents current (amperes), Q is charge (coulombs), and t is time (seconds). This formula calculates the current as the rate of flow of charge. Tip: 1 A = 1 C/s.

2

V = W/Q

V is potential difference (volts), W is work done (joules), and Q is charge (coulombs). It defines potential difference as work done per unit charge. Example: Moving 2 C with 24 J work gives V = 12 V.

3

R = ρl/A

R is resistance (ohms), ρ is resistivity (Ωm), l is length (m), and A is cross-sectional area (m²). This shows resistance depends on material and dimensions. Tip: Longer or thinner wires have higher resistance.

4

P = VI

P is power (watts), V is potential difference (volts), and I is current (amperes). It calculates the power consumed by a device. Example: A bulb at 220 V and 0.5 A uses 110 W.

5

H = I²Rt

H is heat (joules), I is current (amperes), R is resistance (ohms), and t is time (seconds). Joule's law of heating. Tip: Heat increases with the square of current.

6

1/Rp = 1/R₁ + 1/R₂ + ...

Rp is equivalent resistance (ohms) of parallel resistors R₁, R₂, etc. The total resistance decreases in parallel. Example: Two 10 Ω resistors in parallel give 5 Ω.

7

Rs = R₁ + R₂ + ...

Rs is equivalent resistance (ohms) of series resistors R₁, R₂, etc. The total resistance adds up in series. Example: Two 10 Ω resistors in series give 20 Ω.

8

V = IR

V is potential difference (volts), I is current (amperes), and R is resistance (ohms). Ohm's law, fundamental for circuit analysis. Tip: Directly proportional relationship.

9

E = VIt

E is energy (joules), V is potential difference (volts), I is current (amperes), and t is time (seconds). Calculates energy consumed by a device. Example: 220 V, 0.5 A for 1 hour is 396 kJ.

10

P = I²R

P is power (watts), I is current (amperes), and R is resistance (ohms). Alternative power formula, useful when voltage is not known. Derived from P = VI and V = IR.

Worked Examples

1

Ohm’s Law: V = IR

Defines the relationship between voltage, current, and resistance in a conductor. Essential for solving circuit problems. Real-world use: Designing electrical circuits.

2

Series Resistance: Rs = R₁ + R₂ + R₃ + ...

Total resistance in a series circuit is the sum of individual resistances. Tip: Current remains the same across each resistor.

3

Parallel Resistance: 1/Rp = 1/R₁ + 1/R₂ + 1/R₃ + ...

Reciprocal of total resistance in parallel is the sum of reciprocals of individual resistances. Tip: Voltage remains the same across each resistor.

4

Power: P = V²/R

Calculates power using voltage and resistance. Derived from P = VI and Ohm's law. Useful when current is not directly known.

5

Current: I = V/R

Calculates current using voltage and resistance. Direct application of Ohm's law. Example: 12 V across 4 Ω gives 3 A.

6

Energy: E = P × t

Energy consumed is power multiplied by time. Real-world use: Calculating electricity bills. Example: 100 W for 10 hours is 1 kWh.

7

Resistivity: ρ = RA/l

Relates resistance to material properties and dimensions. Tip: Resistivity is a material property, independent of shape.

8

Charge: Q = It

Charge is current multiplied by time. Useful for calculating total charge flow. Example: 2 A for 5 seconds is 10 C.

9

Work: W = VQ

Work done to move charge across a potential difference. Example: Moving 2 C across 12 V requires 24 J.

10

Heat: H = VIt

Heat produced in a resistor is voltage times current times time. Alternative to H = I²Rt, emphasizing voltage's role.

Explore More Electricity Resources

Explore more chapter resources to strengthen your understanding and prepare for exams.

Electricity Frequently Asked Questions

Explore the essential concepts of electricity, including current, circuits, Ohm's Law, resistance factors, and the heating effect of electric current. Learn how these principles apply to various electrical devices.

An electric circuit is a closed path that allows electric charges to flow. It consists of components such as a battery, wires, and resistive elements that form a complete loop, facilitating the movement of current.
Electric current is measured in amperes (A) using an instrument called an ammeter, which must be connected in series within the circuit to obtain an accurate measurement of the flow of charge.
Electric potential difference, measured in volts (V), is defined as the work done to move a unit charge from one point to another in an electric field. It is a crucial factor that drives the flow of current in a circuit.
Ohm's Law states that the potential difference (V) across a conductor is directly proportional to the current (I) flowing through it, expressed mathematically as V = IR, where R is the resistance.
The resistance of a conductor depends on its material, length, and cross-sectional area. Longer conductors have higher resistance, while wider ones have lower resistance.
Resistors are used in circuits to limit current flow and adjust voltage levels. They can be arranged in series or parallel to achieve desired total resistance in a circuit.
The heating effect of electric current, produced when current flows through a resistor, generates heat used in devices like electric heaters and toasters. This effect is also essential for safety features like fuses.
The SI unit of electric current is the ampere (A), which quantifies the flow of electric charge through a conductor.
Electric power (P) is calculated using the formula P = VI, where V is the voltage and I is the current. Power is measured in watts (W).
Ohm's Law is applied in various electrical devices to design circuits that utilize appropriate levels of current and voltage, ensuring functionality and safety in appliances such as bulbs and heaters.
If the resistance in a circuit is increased while maintaining voltage, the current flowing through the circuit decreases, according to Ohm's Law (I = V/R).
Devices like electric irons, heaters, and toasters use the heating effect of electric current to convert electrical energy into thermal energy for practical applications.
Metals are good conductors because they have free electrons that can move easily through the material, allowing electric current to flow with low resistance.
An ammeter is a device used to measure the current flowing through a circuit. It must be connected in series to ensure all current flows through it for accurate readings.
A voltmeter is connected in parallel across the two points of a circuit where the potential difference is to be measured. This configuration allows it to measure the voltage without affecting circuit operation.
In a series circuit, all components are connected in a single path, and the same current flows through each. In a parallel circuit, components are connected across common points, and the voltage across them is the same, allowing for different currents.
A high current can lead to increased heat generation in conductors, potentially causing overheating and damaging components or creating safety hazards such as fires.
Electric potential difference represents the amount of work done (in joules) to move a unit charge from one point to another in an electric field, thus establishing energy transfer.
Fuses are safety devices that protect electrical circuits from excessive current. They disconnect the circuit if the current exceeds a certain level, thus preventing overheating and potential hazards.
The resistance of conductors typically increases with temperature, as increased thermal energy causes more collisions among charge carriers, hindering their flow.
If the voltage is doubled while the resistance remains constant, the power consumed increases by a factor of four, as power is proportional to the square of the voltage (P = V^2/R).
Common materials for electrical resistors include carbon, metal films, and alloys, which are chosen for their ability to provide stable and accurate resistance in circuits.
The resistance of a conductor is inversely proportional to its cross-sectional area; larger areas provide less resistance, allowing for greater current flow.

Electricity PDF Downloads

Download worksheets, revision guides, formula sheets, and the official textbook PDF for Electricity.

Electricity Official Textbook PDF

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Electricity Revision Guide

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Electricity Formula Sheet

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Electricity Practice Worksheet

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Electricity Challenge Worksheet

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Electricity Question Bank

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Electricity Flashcards

Revise key terms and definitions from Electricity with interactive flashcards. Quick recall practice for CBSE Class 10 Science.

These flash cards cover important concepts from Electricity in Science for Class 10 (Science).

1/20

What is electric current?

1/20

Electric current is the flow of electric charge through a conductor, typically measured in amperes (A).

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2/20

What is an electric circuit?

2/20

An electric circuit is a continuous closed path through which electric current flows.

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3/20

What is the formula for electric current?

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3/20

The electric current (I) is given by I = Q/t, where Q is the charge in coulombs and t is the time in seconds.

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4/20

What is the SI unit of electric charge?

4/20

The SI unit of electric charge is the coulomb (C).

5/20

How is current measured?

5/20

Current is measured using an ammeter, which is connected in series in the circuit.

6/20

What is potential difference?

6/20

Potential difference (V) is the work done to move a unit charge from one point to another, measured in volts (V).

7/20

What is the formula for potential difference?

7/20

The potential difference (V) is defined as V = W/Q, where W is work done and Q is charge.

8/20

What is the SI unit of potential difference?

8/20

The SI unit of potential difference is the volt (V).

9/20

What are basic components of a circuit diagram?

9/20

Basic components include a cell (battery), switch, resistor, and connecting wires.

10/20

What does Ohm’s Law state?

10/20

Ohm's Law states that V = IR, where V is potential difference, I is current, and R is resistance.

11/20

What is the SI unit of resistance?

11/20

The SI unit of resistance is the ohm (Ω).

12/20

What factors affect a conductor's resistance?

12/20

Resistance depends on length, cross-sectional area, and material of the conductor.

13/20

How are resistors combined in series?

13/20

In series, the total resistance (Rs) is the sum: Rs = R1 + R2 + R3.

14/20

How are resistors combined in parallel?

14/20

In parallel, the total resistance (Rp) is given by 1/Rp = 1/R1 + 1/R2 + 1/R3.

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What is the property of current in a series circuit?

15/20

The same current flows through all components in a series circuit.

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What is the property of current in a parallel circuit?

16/20

The total current is the sum of currents through each parallel branch: I = I1 + I2 + I3.

17/20

How should an ammeter be connected?

17/20

An ammeter is connected in series to measure current in a circuit.

18/20

How should a voltmeter be connected?

18/20

A voltmeter is connected in parallel across the terminals to measure potential difference.

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What is the heating effect of electric current?

19/20

The heating effect occurs when electric current flows through a conductor, generating heat due to resistance.

20/20

How is Ohm's Law applied practically?

20/20

It helps calculate current, voltage, or resistance in circuits, aiding in design and troubleshooting.

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Practice Electricity with Interactive Duels

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Master Electricity via Live Academic Duels

Challenge your classmates or test your individual retention on the core concepts of CBSE Class 10 Science (Science). Compete in speed-recall question rounds matched explicitly to the latest syllabus milestones for Electricity.

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