Question

(a) If the image formed by a mirror for all positions of the object placed in front of it is always diminished, erect and virtual, name the type of the mirror used and also draw a ray diagram to justify your answer. Write one use such mirrors are put to and why.
(b) Define the radius of curvature of spherical mirrors. Find the nature and focal length of spherical mirror whose radius of curvature is +24 cm.

Answer 1

The type of the mirror is convex mirror.
The ray diagram is shown below:
Use of convex mirror:
Convex mirror is used as rear view mirror in vehicles as it always produce virtual, erect and diminished image of an object. So, images of vehicles that are spreaded over a large area can be seen easily in it.

b) Radius of curvature of a spherical mirror is defined as the distance between centre of curvature and pole of the mirror.

Given, radius of curvature, R = +24 cm.
We know, focal length, $f=\frac{R}{2}=\frac{24}{2}$ $=+12cm$.
Therefore focal length of the spherical mirror is 12 cm and the nature is positive.