Question

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

Answer 1

Hint: For a given prism the refractive index is more for the violet light ray than for the red light ray i.e. the violet light ray is more deviated than the red light ray. If red light replaces the incident violet light, the minimum deviation angle decrees from its earlier value.

Complete step by step solution:
Red waves have a relatively long wavelength (at a range of), and violet waves are much shorter-about half of that. Because violet waves possess the visible light spectrum's shortest wavelength, they carry the most energy. The higher the frequency, the faster the swings and hence the higher the energy.
The Refractive index is inversely proportional to the luminous wavelength. Red has a wavelength higher than violet light and therefore has a smaller refractive index than violet. Again, the minimum deviation angle is directly proportional to the refractive index, and will therefore decrease when replaced by a red light.
The deviation of light is due to the refraction phenomenon. It deviates when light transits from one medium to another (like air to glass). From its original medium prevailing path. This Si is known as light refraction.
The tiniest angle through which an optical element or system bends light. In a prism, the deviation angle is a minimum if the incident and the exiting rays form equal angles with the face of the prism. The angle relative to prism spectroscopes is important because it can be easily determined.

Note: Red light wavelength is greater than violet light's. And the refractive index is inversely proportional to the wavelength of any light. In turn, the angle of minimum deviation with the refractive index has a linear dependence. Thus, when violet light is replaced by red light, the minimum deviation angle decreases.