Question

Figure shows a plane wavefront refracted from air to water using Huygen's principle. The refractive index of water with respect to air is given by,

• A. $\frac{a}{e}$
• B. $\frac{b}{e}$
• C. $\frac{b}{d}$
• D. $\frac{d}{b}$

Answer 1

The correct option is C $\frac{b}{d}$


According to the Snell's law,
$\frac{\sin i}{\sin r}=\frac{{\mu }_2}{{\mu }_1}$

$\Rightarrow \frac{\frac{b}{AB}}{\frac{d}{AB}}=\frac{{\mu }_2}{{\mu }_1}$

Since medium $1$ is air, ${\mu }_1\approx 1$
$\Rightarrow {\mu }_2=\frac{b}{d}$

Hence, $\left(C\right)$ is the correct answer.