A point object in air is placed symmetrically at a distance of 60 cm in front of a concave spherical surface of refractive index 1.5. If the radius…

\[\begin{aligned} & \mu=1.5, u=-60 \mathrm{~cm}, R=-20 \mathrm{~cm}, \mathrm{v}=? \\ & \frac{\mu}{\mathrm{v}}-\frac{1}{u}=\frac{\mu-1}{R} \\ & \frac{1.5}{\mathrm{v}}-\frac{1}{(-60)}=\frac{1.5-1}{(-20)} \\ & \mathrm{v}=-36 \mathrm{~cm} \end{aligned} \] & \[\begin{array}{c|l} 1 / 2 & \\ 1 & \\ 1 / 2 & 2 \end{array} \]