Question

A convex mirror has focal length 20 cm. An object placed in front of it at a distance of 10cm. its image is formed at what distance?

Answer 1

Dear Student ,
Here in this case applying the equation of spherical mirror for convex lens we get ,
$$\begin{gathered} \frac{1}{v}+\frac{1}{u}=\frac{1}{f} \\ Now,u=-10cm,andf=-20cmandv=imagedis\tan ce=? \\ So,\frac{1}{v}-\frac{1}{10}=-\frac{1}{20} \\ \Rightarrow \frac{1}{v}=\frac{1}{10}-\frac{1}{20} \\ \Rightarrow \frac{1}{v}=\frac{1}{20} \\ \Rightarrow v=20cm \end{gathered}$$
Regards