Question

A converging lens is used to focus light from a small bulb onto a book. The lens has a focal length of 10.0 cm and is located 40.0 cm from the book. Determine the distance from the lens to the light bulb.

Answer 1

Answer:

$u=13.3cm$

Explanation:

From the question we are told that:

Focal Length $F=10.0cm$

Distance $d=40cm$

Generally the equation for Focal length  is mathematically given by

$\frac{1}{f}=\frac{1}{u}+\frac{1}{v}$

$\frac{1}{10}=\frac{1}{u}+\frac{1}{40}$

$\frac{1}{u}=\frac{3}{40}$

$u=13.3cm$