Question

A concave mirror produces three times enlarged image of an object placed at 10cm in front of it.
Calculate the radius of curvature of the mirror.

Answer 1

$$\begin{gathered} DearStudent, \\ Given, \\ m=3,u=-10cm \\ Wehave, \\ m=-\frac{v}{u} \\ \Rightarrow \\ 3=-\frac{v}{-10}=\frac{v}{10} \\ \Rightarrow \\ v=30cm \\ Also, \\ \frac{1}{f}=\frac{1}{v}+\frac{1}{u} \\ \Rightarrow \\ \frac{1}{f}=\frac{1}{30}-\frac{1}{10} \\ \frac{1}{f}=\frac{1-3}{30}=\frac{-2}{30} \\ \Rightarrow \\ f=-\frac{30}{2}=-15cm \\ Magnitudeofradiusofcurvatureis, \\ R=2f=2\times 15=\mathbf{30}\mathit{c}\mathit{m} \\ Regards. \end{gathered}$$