Question

During dispersion through the prism, red light travels fastest and violet travels slowest of all the seven colours. As a result:
A) Red bends the least and the violet bends the most.
B) Red bends the most and violet bends the least.
C) Both red and violet bend the least of all colours.
D) Both red and violet bend the most of all colours.

Answer 1

Hint:The dispersion is defined as the phenomenon in which the phase velocity depends on the frequency of the wave. Phase velocity is the speed at which any wave propagates in some medium. Dispersion phenomenon also happens in the sound and not only in the wave optics.

Complete answer:
It is given in the problem that when a beam of light travels in the prism then the red light travels fastest and violet travels slowest of all seven colours and we need to select the correct option for this problem.

In VIBGYOR the slowest to fastest speed of the colours are from violet to the red, which means that violet has slowest speed while red has maximum speed. Whenever a light is going from the rarer to denser medium then the light bends towards the normal and whenever the light moves from rarer to denser the light moves away from normal. The speed of red light is fastest and therefore there is least bending of red light whereas the speed of the violet light is slowest and hence it bends the most of all the colours.

The red colour bends the least and the violet bends the most.

The correct answer for this formula is option A.

Note:A beam of light consists of seven colours unless it is a monochromatic light and when a beam of light is passed through a prism the seven colours get dispersed on a screen. The seven colours of the light are red, orange, yellow, green, blue, indigo and violet also known as VIBGYOR.