Suppose the farthest distance a person can see without visual aid is 53 cm.
(a) what is the focal length of the corrective lens that will allow the person to see very far away?
(b) is the lens converging or diverging?
(c) the power p of a lens (in diopters) is equal to 1/f, where f is in meters. what is p for the lens?

a. 53cm b. Diverging c. 0.02dioptres

Explanation:

Since the person in question cannot see far object clearly, it shows that the individual is suffering from myopia (short sightedness).

If the object distance (u) is 53cm. for the person to be able to see far way, it means the image must be at infinity. This shows image distance v is infinity. Using the lens formula

1/f = 1/u+1/v

1/f = 1/53 + 1/Infinity

1/f = 1/53 + 0

f=53cm

b) The lens used is concave lens (diverging lens) to diverge all rays outwards

c) Power of a lens P will be 1/53.

P = 0.02dioptres