Explanation:

The process of banding of seven colours is called dispersion. When a beam of white light is passed through a prism, it gets refracted, and different colours bend at different angles. As a result, a band of seven colours is formed, which is called a spectrum.

Dispersion:
Dispersion is the phenomenon of splitting light into its constituent colours. It occurs when light passes through a medium, such as a prism or a raindrop. In a medium, the speed of light varies with the wavelength of light. As a result, different colours of light bend at different angles when they pass through the medium. The amount of bending depends on the refractive index of the medium, which is the measure of how much the speed of light is reduced as it passes through the medium.

Spectrum:
A spectrum is a band of colours formed when white light is dispersed. The seven colours of the spectrum are red, orange, yellow, green, blue, indigo, and violet. The spectrum is often represented as a rainbow. Each colour in the spectrum has a different wavelength and frequency. Red has the longest wavelength and the lowest frequency, while violet has the shortest wavelength and the highest frequency.

Reflection:
Reflection is the phenomenon of bouncing back of light from a surface. When light falls on a surface, it can either be absorbed or reflected. The angle of incidence of the light is equal to the angle of reflection. This is known as the law of reflection.

Normal:
The normal is an imaginary line perpendicular to the surface of the medium. When a ray of light falls on a surface, the angle of incidence is measured from the normal. The angle of reflection is also measured from the normal.