Question

An object is placed to the left of a convex mirror, such that the object-to-image distance is 140 cm.

Answer 1

Answer:

The focal length of the mirror is 52.5 cm.

Explanation:

Given that,

Object to Image distance d = 140 cm

Image distance v= 35 cm

We need to calculate the object distance

$u = d-v$

$u = 140-35=105\ cm$

We need to calculate the focal length

Using formula of mirror

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

Put the value into the formula

$\dfrac{1}{f}=\dfrac{1}{-105}+\dfrac{1}{35}$

$\dfrac{1}{f}=\dfrac{2}{105}$

$f=52.5\ cm$

Hence, The focal length of the mirror is 52.5 cm.