Question

A man can see the objects up to a distance of one metre from his eyes. To see objects at infinity, he needs a lens of focal length

• A. 0.5 D
• B. +1.0 D
• C. +2.0 D
• D. –1.0 D

Answer 1

The correct option is D –1.0 D

For correcting the myopic eye, the concave corrective lens should form the image for an object at infinity at the far point of the defective eye.
Applying sign convention, f = –(far point of myopic eye) = – 100 cm. So power of the lens $P=\frac{100}{f}=\frac{100}{-100}=-1D$