Question

A man 1.8 m tall wishes to see full-length image in a plane mirror. The length of the shortest mirror in which he can see his entire image is:

(Assume that the mirror is hanged vertically on a wall in front of the man).

• A. $0.6m$
• B. $0.9m$
• C. $1.2m$
• D. $1.5m$

Answer 1

The correct option is B $0.9m$

Length of the shortest mirror in which a man of height h can see his body is $\frac{h}{2}$.
So, a man of height $1\cdot 8m$ can see his entire image in $\frac{1\cdot 8}{2}=0.9m$.