Question

You have a lens whose focal length is –6.25 cm. You place an object on the axis of the lens at a distance of 10.7 cm from it. How far is the object\'s image from the lens (as a positive quantity)?

Answer 1

Answer:

3.95 cm

Explanation:

focal length of the lens, f = - 6.25 cm

distance of object from the lens, u = - 10.7 cm

Let the distance of image from the lens is v.

Use lens equation

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

$\frac{1}{-6.25}=\frac{1}{v}+\frac{1}{10.7}$

$\frac{1}{-6.25}-\frac{1}{10.7}=\frac{1}{v}$

$\frac{1}{v}=\frac{-10.7-6.25}{66.875}$

v = - 3.95 cm

Thus, the distance of image from the lens is 3.95 cm as the same side of object.