Question

An object $1 \,cm$ tall is placed $4\,cm$ in front 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 $4 \,m$
• D. Plane mirror of height $12 \,cm$

Answer 1

Answer: (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)} $
$\Rightarrow f=-6 \,cm$
$\Rightarrow R=2 f=-12 \,cm$