Question

An object 6cm high is placed 30cm in front of a convex mirror of focal length 15cm. Find the image position and determine it's height

Answer 1

Height of object$(h)=6\space cm$

Focal length of mirror$(f)=+15\space cm$

Distance of the object from mirror$(u)=-30\space cm$

Using mirror formula:

$\dfrac{1}{u}+\dfrac{1}{v}=\dfrac{1}{f}\\\Rightarrow\dfrac{1}{v}=\dfrac{1}{15}-\dfrac{1}{(-30)}$

$\Rightarrow v=10\space cm$

Height of image$(h')=\dfrac{10}{(-30)}\times6=-2\space cm$

Negative sign indicates that the image formed is inverted