Q. An object $1cm$ tall is placed $4\ cm$ infront of a mirror. In order to produce an upright image of $3\ cm$ height one needs a
A) Convex mirror of radius of curvature $12\ cm$
B) Concave mirror of radius of curvature $12\ cm$
C) Concave mirror of radius of curvature $4\ cm$
D) Plane mirror of height $12\ cm$
Explanation
(b) Erect and enlarged image can produced by concave mirror
$\frac{I}{O} = \frac{f}{f - u} \Rightarrow \frac{+ 3}{+ 1} = \frac{f}{f - ( - 4)} \Rightarrow f = - 6\ cm$
$\Rightarrow R = 2f = - 12\ cm$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.