Question

A young boy can adjust the power of his eye
lens between 50 D and 60 D the distance of his
retina from the eye lens is (his far point is infinity)​

Answer 1

Explanation:

When the eye is fuly relaxed, its focal length is largest and the power of the eye lens is minimum. This power is 50 D according to the given data. The focal lengts is 150m=2cm. As the far point is at infinity, the parallel rays coming from infinity are focussed on the retiN/A in the fuly relaxed condition. HEnce, the distance of the retinN/A from the lens equals the focal length which is 2 cm.

b. when the eye is focussed at the near point, the power is maximum which is 60 D. the focal lenth in this case is f=160m=53cm.Theima≥isformedontheretiNAandthusv=2cm.Wehave,1/v-1/u=1/for1/u=1/v-1/f=1/(2cm)-3/(5cm)oru=-10cm`

The near point is at 10 cm