Question

A near sighted person cannot see distinctly beyond 50cm from his eye. The power in diopter of spectacle lenses which will enable him to see distant objects clearly is

Answer 1

hopefully this helps you have a good day

Answer 2

The ‘power’ in diopter of ‘spectacle lenses’ which will enable him to see ‘distant objects’ clearly is -2.0 D.

Given:

Distance of the far point = 50 cm

Power of lens (P) = Need to calculate  

Since:

f = -x  

hence f = - 50 cm  

The formula of power and f can be written as:

$P=\frac{100}{f}$

Plug the given  value of  in the formula:

$P=\frac{100}{-50}=-2.0 D$

Hence a near sighted person cannot see distinctly beyond 50 cm from his eye.