Given below is a diagram depicting a defect of the human eye. Study the same and then answer the questions that follow: Given below is a diagram depicting a defect of the human eye. Study the same and then answer the questions that follow:
Name the type of lens used to correct this defect.
Topic: Correction of myopia
Answer
A CONCAVE (diverging) LENS.
A concave lens DIVERGES the rays slightly before they enter the eye. The over-converging eye then has less bending left to do, and the focus is pushed BACK onto the retina.
DECIDE IT BY SHAPE rather than memory: a CONCAVE lens is thin in the middle and spreads rays APART; a CONVEX lens is thick in the middle and brings them TOGETHER. If the focus is forming too early, you need to spread the rays.
Parts (i), (ii) and (iii) form one chain — defect, cause, lens — so getting the first right makes the other two follow automatically.