Physics - Geometrical Optics Question with Solution | TestHub

The correct option is (C).Consider the labeled figure. The fish appears at an apparent depth h๘ while the real depth is $h$. In triangle $\mathrm{OPF}:\tan (\mathrm{i})=\frac{\mathrm{P}}{\mathrm{h}}\simeq \sin (\mathrm{i})$ In triangle OPA: $\tan (\mathrm{r})=\frac{\mathrm{P}}{{\mathrm{h}}^{\prime }}\simeq \sin (\mathrm{r})$ For small angles $\theta ,\mathrm{tam}\theta \simeq \sin \theta$ can be taken. Using smell's law of refraction: $1\times \sin (\mathrm{r})=\mu \times \sin (\mathrm{i})$ Inserting expressions for $\sin (\mathrm{i})$ and $\sin (\mathrm{r})1\times \frac{\mathrm{P}}{{\mathrm{h}}^{\prime }}=\mu \times \frac{\mathrm{P}}{\mathrm{h}}$ $\mathrm{h}=\mu {\mathrm{h}}^{\prime }$ Given, ${\mathrm{h}}^{\prime }=30\mathrm{cm}$ and $\mu =\frac{4}{3}$, therefore real depth $\mathrm{h}=40\mathrm{cm}$.