Question

If the velocity and wavelength of light in air is $v_a$ and $\lambda_a$, and that in water is $v_w$ and $\lambda_w$. Then the refractive index of water is

• A. $\frac{v_{w}}{v_{a}}$
• B. $\frac{v_{a}}{v_{w}}$
• C. $\frac{\lambda_{w}}{\lambda_{a}}$
• D. $\frac{v_{a}\lambda_{a}}{v_{w}\lambda_{w}}$

Answer 1

Answer: (B)

According to Snell's law
$_{a}\mu_{w} = \frac{v_{a}}{v_{w}} = \frac{\lambda_{a}}{\lambda_{w}} = \frac{\mu_{w}}{\mu_{a}} $
or $\mu_{w} = \frac{v_{a}}{v_{w}} \quad\left(\because\mu_{a}=1\right)$