Question

21. A small object is placed at right angles to the axis of a fixed concave
mirror so as to form (i) a real (ii) a virtual image, twice as long as the
object. if the radius of curvature of the mirror is 40cm, what is the
distance between the two images?
Ans: 60cm
om
chat and in ito​

Answer 1

Answer: 60 cm

Explanation:

Given that:

Radius of curvature (R) = 40 cm

Radius of curvature is 2 tines the Focal length:

Focal length (f) = 40/2 = 20

Object distance = u

Image distance = v

Image (v) = 2u

1/v + 1/u = 1 /f

1/2u + 1/u = 1/20

(1 + 2) /2u = 1/20

3 / 2u = 1/20

2u = 60

u = 60/2

u = 30 cm

v = 2u

v = 2(30)

v = 60 cm