Question

A motor car is fitted with a convex driving mirror of focal length 20 cm. A second motor car $2$ m broad and $21.6$ m high is 6 m away from the first car. The position of the second car as seen in the mirror of the first car is :

• A. $15.4cm$
• B. $17.4cm$
• C. $19.4cm$
• D. $25cm$

Answer 1

The correct option is C $19.4cm$

Here,

Object distance, $u=-600cm$

Focal length, $f=+20cm$

Using mirror formula,

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

$\frac{1}{\nu }+\frac{1}{-600}=\frac{1}{20}$

$\nu =\frac{600\times 20}{600+20}=19.4cm$