An object is placed at a distance of $\displaystyle 60$ cm from a concave lens of focal length $\displaystyle 30$ cm. Use lens formula to find the position of the image formed in this case.

\[\begin{aligned} & \mathrm{u}=-60 \mathrm{~cm} \quad \mathrm{f}=-30 \mathrm{~cm} \\ & \frac{1}{f}=\frac{1}{v}-\frac{1}{u} \\ & \frac{1}{-30 \mathrm{~cm}}=\frac{1}{v}-\frac{1}{-60 \mathrm{~cm}} \\ & \frac{1}{v}=\frac{1}{-30}-\frac{1}{60} \\ & \frac{-3}{60 \mathrm{~cm}}=\frac{1}{v} \Rightarrow \mathrm{~V}=-20 \mathrm{~cm} \end{aligned} \] Position of image is $\displaystyle 20$ cm from a concave lens.