Question

Name the defect vision due to
a) Excesive curvature of eye lens
b) Focal length of the eye lens is too long

Answer 1

$\boxed{\sf{\red{\huge{\bold{Answer}}}}}$

The optical defects present in the following conditions are :

1. Excessive curvature of the eye lens represents increase in power of the lens. This also means that the focal length of the lens decreases. As a result of this defect , the light rays meet the Principle Axis before the retina.

This condition is called Myopia.

2. When focal length becomes very long, in return the power of lens decreases. Hence converging power decreases. As a result ,the light rays from objects meet the Principle Axis after the retina.

This condition is called Hypermetropia.

Answer 2

a)Mypoia➠ Mypoia is that defect of eye due to which a person cannot see the distance objects clearly.

Maypoia is caused either due to high converging power of eye-lens or due to eye- ball being too long.

b)Hypermetropia➠ Hypermetropia is that defect of eye due to which a person cannot see the nearby objects clearly.

Hypermetropia is caused either due to low converging power of eye-lens or due to eye-ball being too short.