Question

a motor car is fitted with a rear view mirror of focal length 20 cm a second car 2m broad and 21.6m high is 6 m away from first car .find the position of second car as seen in the mirror of first car​

Answer 1

Answer:

The position of second car as seen in the mirror of first car​ is 19.35cm behind the mirror.

Explanation:

Given :

Distance of Second motor car from first= 6m= - 600 cm  

Focal length of convex mirror =f= 20cm

Image dstance =V=?

By mirror formula :

1/f=1/v+1/u

1/v=1/f-1/u

1/v= 1/20+1/600

=600+20/12000

v= 19.35cm

∴ The position of second car as seen in the mirror of first car​ is 19.35cm behind the mirror.

Answer 2

Answer:

The position of second car as seen in the mirror of first car​ is 19.35 cm back of the mirror.

Explanation:

Given that,

Focal length f = 20 cm

Distance of the second car from first u = -600 cm

The position of second car as seen in the mirror of first car​ is

Using mirror's formula

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

$\dfrac{1}{20}=\dfrac{1}{v}+\dfrac{1}{-600}$

$\dfrac{1}{v}=\dfrac{1}{20}+\dfrac{1}{600}$

$\dfrac{1}{v}=\dfrac{31}{600}$

$v = 19.35\ cm$

Hence,  The position of second car as seen in the mirror of first car​ is 19.35 cm back of the mirror.