Q. An object of length $6\ cm$ is placed on the principal axis of a concave mirror of focal length $f$ at a distance of $4f$. The length of the image will be
A) 2 $cm$
B) 12 $cm$
C) 4 $cm$
D) $1.2\ cm$
Explanation
(a) $\frac{I}{O} = \frac{f}{f - u}\ \Rightarrow \frac{I}{+ 6} = \frac{- f}{- f - ( - 4\ f)} \Rightarrow I = - 2\ cm$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.