Question

In image formation from spherical mirrors, only paraxial rays are considered because they

• A. are easy to handle geometrically
• B. are not parallel to principal axis
• C. form nearly a point image of a point source
• D. are far from principal axis

Answer 1

The correct option is C form nearly a point image of a point source

Paraxial rays are rays having very small angle with the principal axis. These rays are parallel to the principal axis and lies close to it.
The paraxial rays from the far point source get converged at the same point after reflection from a concave mirror, thus giving a sharp point image of a point source.