Calculate the focal length of a reading glass of a person if his distance of distinct vision is 75 cm.

Options

A. 100.4cm
B. 75.2cm
C. 37.5cm
D. 25.6cm

Answer

C

Explanation

`v= - 75cm, u= -25cm`
`(1)/(f) = (1)/(u) + (1)/((-v)) = (1)/(25) + (1)/(-75) = (2)/(75) rArr f= (75)/(2)` we get f= 37.5cm