## In This post you will get answer of Q.

The power of a lens, a short sighted person uses is -2 D. Find the maximum distance of an object which he can see without spectacles:

Solution:

## Image is formed at focus. We know that Power

$ (P)=frac{text{1}}{text{focal},text{length},text{(m)}} $ Given $ P=-2D $

$ therefore $ $ text{Focal},text{length},=-frac{1}{2}=-0.5,m $

$ Rightarrow $ $ F=-50,cm $

Hence, maximum distance of an object, which he can see without spectacles is 50 cm.