Question

a doctor prescribes a corrective lens power -0.5D to a person. The focal length of lens and the type is
a) -2m and concave lens
b) +2m and convex lens
c) + 2m and concave lens
d) - 2m and convex​

Answer 1

Answer:

b is the correct answer

+2m and convex lens

Answer 2

Answer:

a)-2m and concave lens

Explanation:

The power of the lens is said to be 1 dioptre if the focal length of the lens is 1metre. That means, if the corrective power of the lens is +0.5D, the required lens is a convex lens of focal length +2m. In the same way, a power of -2.0D means a concave lens of focal length -0.5m.