Q. A 16 cm long image of an object is formed by a convex lens on a screen. On moving the lens towards the screen, without changing the positions of the object and the screen, a 9 cm long image is formed again on the screen. The size of the object is
A) 9 cm
B) 11 cm
C) 12 cm
D) 13 cm
Explanation
(c) $y = \sqrt{y_{1} \times y_{2}} = \sqrt{16 \times 9} = 4 \times 3 = 12$ cm
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.