How does the angle of minimum deviation of a glass prism vary, if the incident violet light is replaced by red light? Give reason.

The angle of minimum deviation is given by $\left.\mathrm{\delta m}=\left({\mathrm{n}}_{21}-2\right)\mathrm{A}\right)$
${\mathrm{\delta }}_{\text{red }}>{\mathrm{\delta }}_{\text{violet }}$
We know that,
$\mathrm{\lambda }\propto \left(\frac{1}{\mathrm{\mu }}\right)$
So, ${\mathrm{\mu }}_{\text{red }}<{\mathrm{\mu }}_{\text{violet }}$
So, ${\mathrm{\lambda }}_{\text{red }}>{\mathrm{\lambda }}_{\text{violet }}$
If violet light is replaced by red light its refractive index decreases and angle of minimum deviation decreases.