Single Answer MCQ
Q-00106620
What is the focal length of a concave mirror if the object distance is 30 cm and the image distance is -15 cm?
1
-10 cm
2
-20 cm
3
-15 cm
4
-5 cm
Answer and Solution
Answer
A. -10 cm
Solution:
Using the mirror formula: 1/f = 1/v + 1/u. Here, u = -30 cm and v = -15 cm. Thus, 1/f = (1/-15) + (1/-30) = -1/10. Therefore, f = -10 cm.
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