Question

(A) Define radius of curvature of the spherical mirror (B) the radius of curvature of a spherical mirror is 20 cm. find its focal length.

Answer 1

A) Radius of curvature of a spherical mirror is the radius of imaginary sphere of a which mirror is a part. it is shown by R.

B) Focal length(f) = R/2 = 20/2 = 10 cm.

Additional information :

• The distance of the principal focus from the pole is called focal length.

• The distance of the object from its pole is called as object distance.

• The distance of the image from the pole of the mirror is called image distance.

• The diameter of the reflecting surface of a spherical mirror is called its aperture.

Answer 2

Answer:

1. Define the principle focus of a concave mirror.

Ans. Principal focus of a concave mirror is the point on its principal axis, where light rays coming parallel to principal axis actually converge after reflection from mirror.

2. The radius of curvature of a spherical mirror is 20 cm. what is its focal length?

Ans. Focal length (f)= R/2 = 20 cm/2 = 10 cm.