i. Name the defect shown in the figure. ii. Give two possible reasons for this defect of eye in human beings.

Question

Given below is a diagram showing a defect of human eye.

i. Name the defect shown in the figure.

ii. Give two possible reasons for this defect of eye in human beings.

iii. Name the type of lens used to correct the eye defect.

iv. Draw a labelled diagram to show how the defect is rectified by using the lens.

Answer 1

A lens having both spherical surfaces puffed up outwards is called a convex lens or double convex lens or biconvex lens. It is thicker in the middle than at the edges.

[Note: A convex lens is also called a converging lens.]