A car is fitted with a convex side-view mirror of focal length 20 cm. A second car 2.8m behind the first car is overtaking the first car at a relative speed of 15 `m/s`. The speed of the image of the second car as seen in the mrror of the first one is:

Options

A. `5.79cm, 6.9 cm`
B. `6.45 cm, 5.16 cm`
C. `2.7 cm, 4.8 cm`
D. `0.1 m, 0.3m`

Answer

B

Explanation

`m=-(v)/(u)=-(600)/(31)xx(1)/(-600)=(1)/(31)`
Breadth of image
`=(1)/(31)xx200cm =6.45 cm`
Height of image `=(1)/(31)xx160cm= 5.16cm`.