Question

When white light enters a prism, its gets splits into its constituent colours. This is because of:

• A. high density of prism material
• B. $\mu$, which is different for different wavelengths
• C. diffraction of light
• D. interference of light

Answer 1

Answer: (B)

$\mu$, which is different for different wavelengths

Refractive index of a medium is dependent on the wavelength of light. White light constitutes of many colours. According to snell's law,

$\mu =\frac{\sin i}{\sin r}$

As $\mu$ is different for different wavelengths, $r$ is different too, and hence each wavelength is deviated by a different amount. This leads to the splitting of colours in white light.