Question

A security mirror used in a big showroom has radius of curvature 5m. If a

customer is standing at a distance of 20m from the cash counter ,find the position,

nature and size of the image formed in the security mirror.​

Answer 1

A security mirror used in a big showroom has radius of curvature 5m. If a

customer is standing at a distance of 20m from the cash counter ,find the position,

nature and size of the image formed in the security mirror.

Answer 2

It is a convex mirror.So focal length should be positive

Radius of curvature R= + 5 m

∴ focal length f = 5/ 2 = +2.5 m

Object distance u= -20m

Mirror formula 1/v + 1/ u = 1/ f

1/ v + 1/ −20 = 1/ 2.5 1

v = 1/ 20 + 1/ 2.5

1/ v = 1/ 20 + 10/ 25

1/ v = 5+ 40 / 100 = 45/ 100

v = 100/ 45 = 20/ 9 = +2.2m

Therefore the Nature of image = virtual and erect image

and the Size of image : diminished image

hope it helps .

hru jeswin

- saireen