Question

Woman has a near point of 75.0 cm. What focal length, f, is necessary for the corrective lens so that he can hold his physics book 20.0 cm from his eye and read the pearls of wisdom contained therein clearly?

Answer 1

The focal length of the lens must be 27.3cm

Step-by-step explanation:

Image distance= -75 cm

Object distance= 20.0cm

From:

1/v + 1/u = 1/f

-1/75+ 1/20 = 1/f

11/300= 1/f

f= 300/11

f= 27.3cm

The focal length of the lens must be 27.3cm