a) An object is kept between centre of curvature and principal focus of a concave mirror. Write the nature of the image formed.
b) Define focal length of a convex mirror. Write the relationship between focal length and radius of curvature of a convex mirror.

Explanation

(a)
Real and inverted
(b) The distance between the pole and the principal focus of a convex mirror is called the focal length of a convex mirror.
The relationship between focal length and radius of curvature of a convex mirror.
The radius of curvature is found to be equal to twice the focal length.
R=2f
This implies that the principal focus of a spherical mirror lies midway between the pole and centre of curvature.