Question

A convex mirror of radius of curvature 4 m is used as rear -view mirror in an automobile. If a vehicle of size 4 m is at a distance of 5 m from the mirror, what is the position of the image and size of the image?

• A. $\frac{5}{6}m,\frac{1}{6}m$
• B. $\frac{10}{7}m,\frac{8}{7}m$
• C. $\frac{6}{5}m,\frac{1}{16}m$
• D. $\frac{10}{13}m,\frac{4}{17}m$

Answer 1

The correct option is B $\frac{10}{7}m,\frac{8}{7}m$

$\frac{1}{v}+\frac{1}{u}=\frac{1}{f}$

$\therefore \frac{1}{v}+\left[\frac{1}{-5}\right]=\frac{1}{2}$

$v=\frac{10}{7}m$

And $magnification=\frac{-v}{u}=\frac{h_1}{h_0}$

$h_1=\frac{8}{7}$