Physics - Geometrical Optics Question with Solution | TestHub

Intensity of incident light = $I_0$

Intensity of light reflected by the upper surface is $25\%$ of $I_0$:

$I_1=\frac{25}{100}{I}_0=\frac{I_0}{4}$

Intensity of light transmitted into the glass plate:

$I_t=I_0-I_1=I_0-\frac{I_0}{4}=\frac{3I_0}{4}$

Intensity of light reflected from the lower surface is $50\%$ of the transmitted light:

$I_2=\frac{50}{100}{I}_t=\frac{1}{2}\times \frac{3I_0}{4}=\frac{3I_0}{8}$

The ratio of $I_2$ to $I_1$ is:

$\frac{I_2}{I_1}=\frac{\frac{3I_0}{8}}{\frac{I_0}{4}}=\frac{3}{8}\times 4=\frac{3}{2}$

Answer: $3:2$