Question

) The focal length of a rear view mirror in a moving car is 1 m. A truck is coming from behind, at a distance of 5 m. Calculate the i) Position and ii) size of the image relative to the size of the truck.

Answer 1

Answer:

Radius of curvature, R=2m

object distance, μ=3.5m

focal length, f=

2

R

=

2

2

f=1m

from mirror formula,

f

1

=

μ

−v

1

1

=

v

1

−

3.5

1

⇒

v

1

=1+

3.5

1

v

1

=

7

9

v=

9

7

m=0.78m

Magification, m=−

μ

v

=+

9×3.5

7

m=

9

2

=0.22

Image will be formed at 0.78m & will be virtual crect and diminished.

Image will be 0.22 times the truck.