Question

Radius of curvature of concave mirror is 50cm and image is placed 75 cm distance from the pole . what is the object distance?​

Answer 1

Answer:

object distance=p=50cm

Radius of curvature=R=60cm

then f=R/2

f=60/2

f=30cm

image distance=q=?

using mirror formula

1/f=1/p+1/q

1/30=1/50+1/q

1/30–1/50=1/q

(5–3)/150=1/q

2/150=1/q

2q=150

q=75

image distance=75cm

Answer 2

Answer:

• The radius of curvature of the lens = 50 cm.
• The image distance = 75 cm.

We need to find the object distance.

We know that, the mirror formula :-

1/f = 1/u + 1/v

The radius of curvature is given as 50 cm.

So, f = 25 cm.

Hence,

1/25 = 1/u + 1/75

1/u = 1/25 - 1/75

1/u = (3 - 1)/75

1/u = 2/75

u = 75/2

So, the object distance = 37.5 cm.