Physics - Geometrical Optics Question with Solution | TestHub

$:h_0=5\mathrm{cm},h_i=?$ $u=-100\mathrm{cm},R=-20\mathrm{cm}.\therefore f=-10\mathrm{cm}$ Using mirror formula, $\begin{array}{rl}& \frac{1}{v}+\frac{1}{u}=\frac{1}{f}\Rightarrow \frac{1}{v}-\frac{1}{100}=-\frac{1}{10}\\ & \frac{1}{v}=\frac{1}{100}-\frac{1}{10}=\frac{1-10}{100}=-\frac{9}{100}\\ & \therefore v=-\frac{100}{9}\mathrm{cm}.\\ & \frac{h_i}{h_0}=\frac{v}{u}\Rightarrow \frac{h_i}{5\mathrm{cm}}=\frac{(100/9)}{100}=\frac{1}{9}\\ & \therefore h_i=5/9=0.55\mathrm{cm}.\end{array}$