Question

(a) Define a spherical mirror.
(b) Distinguish between a concave mirror and a convex mirror.
(c) What is the difference between a real image and a virtual image?

Answer 1

(a) A spherical mirror is a mirror which has the shape of a piece cut out of a spherical surface. There are two types of spherical mirrors: concave, and convex.

(b) Difference between concave and convex mirrors:

i) In a concave mirror the reflecting surface is in the inner part of the sphere of which the mirror is a part. Whereas in convex mirror the reflecting surface is at the outer side of the sphere of which the mirror is a part.

ii) In a concave mirror the image formed can be either real and inverted or virtual and erect, but in a convex mirror always the image formed is virtual and erect.

iii) The magnification of a concave mirror can be either greater, equal or less than one. But in a convex mirror, the magnification is always less than one.

(c) Difference between real and virtual images:

i) A real image can be caught on a screen whereas a virtual image cannot be caught on a screen.

ii) A real image is always inverted whereas a virtual image is always erect.

iii) A real image is formed by the actual intersection of light rays whereas a virtual image is formed by the imaginary intersection of light rays.