State the rules to draw a ray diagram of a convex lens with proper figures.

Explanation

i. Rule I: When the incident ray is parallel to the principal axis, the refracted ray passes through the principal focus.

ii. Rule II: When the incident ray passes through the principal focus, the refracted ray is parallel to the principal axis.

iii. Rule III: When the incident ray passes through the optical centre of the lens, it passes without changing its direction.