Question

student conducts an activity using a concave mirror with focal length of 10 cm. He placed the object 15 cm from the mirror. Where is the image likely to form?​

Answer 1

Given:

Mirror has focal length of 10 cm and object distance is 15 cm.

To find:

Image distance ?

Calculation:

Applying MIRROR FORMULA:

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

$\sf \implies\: \dfrac{1}{ - 10} = \dfrac{1}{v} + \dfrac{1}{ - 15}$

$\sf \implies\: - \dfrac{1}{10} = \dfrac{1}{v} - \dfrac{1}{ 15}$

$\sf \implies\: \dfrac{1}{v} = - \dfrac{1}{10} + \dfrac{1}{15}$

$\sf \implies\: \dfrac{1}{v} = \dfrac{ - 3 + 2}{30}$

$\sf \implies\: \dfrac{1}{v} = \dfrac{ -1}{30}$

$\sf \implies \: v = - 30 \: cm$

So, image is formed at -30 cm from mirror.