Question

a concave mirror of radius 30 cm is placed in water. its focal length in air and water differ by. a)15 b) 20 c) 30 d)0​

Answer 1

The focal length in air and water differ by 15 cm.

Explanation:

It is given that:

Radius of curvature of the concave mirror, R = 30 cm (it have negative sign)

To Find: Focal length "f" = ?

As we know that the focal length is half of the radius of curvature.

So

R = 2f

f = R / 2

f = 30 cm / 2 = 15 cm

Thus, the focal length in air and water differ by 15 cm.

Also learn more

Radius of curvature of a concave mirror is 25 cm what is its focal length?

https://brainly.in/question/6742112

Answer 2

Explanation:

hope this will helpu mark me brainlist