Question

Four different colours of light red, yellow, blue, and violet are incident on a prism at the same angle. The order of the angles of emergence will be:

• A. $\text{red}>\text{blue}>\text{yellow}>\text{violet}$
• B. $\text{red}<\text{blue}<\text{yellow}<\text{violet}$
• C. $\text{red}<\text{blue}>\text{yellow}<\text{violet}$
• D. $\text{violet}>\text{blue}>\text{yellow}>\text{red}$

Answer 1

The correct option is D $\text{violet}>\text{blue}>\text{yellow}>\text{red}$

The angle of emergence depends on the refraction of the light ray inside the prism.
All colours have different wavelength and the refractive index will be different for different colours of light.
Therefore, the angle of refraction is not same for all the colours, thereby the angle of emergence will not be the same.
The order of wavelength is
$\text{violet}>\text{blue}>\text{yellow}>\text{red}$
The order of angle of emergence will be as follows
$\text{violet}>\text{blue}>\text{yellow}>\text{red}$