Question

An object $1cm$ in length is placed at a distance of $10cm$ in front of a convex mirror of radius of curvature $15cm$. Find the position of image.

• A. $0.233cm$
• B. $150cm$
• C. $4.28cm$
• D. $5cm$

Answer 1

Answer: (C)

$4.28cm$

Given,

Object distance, $u=-10cm$

Focal length, $f=\frac{R}{2}=\frac{15}{2}=7.5cm$

Using mirror formula,

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

$\frac{1}{7.5}=\frac{1}{v}+\frac{1}{-10}$

$\frac{1}{v}=\frac{1}{7.5}+\frac{1}{10}$

$\frac{1}{v}=\frac{4+3}{30}=\frac{7}{30}$

$v=\frac{30}{7}=4.28cm$

Hence, the correct answer is OPTION C.