What is dispersion of light and how does it occur?

Dispersion of light is the process where white light separates into its constituent colours when passing through a prism.

Dispersion of light is a fascinating phenomenon that occurs when light passes through a medium like a glass prism. This process is responsible for the beautiful spectrum of colours we see in a rainbow. The term 'dispersion' refers to the splitting of white light into its seven constituent colours - red, orange, yellow, green, blue, indigo, and violet. This happens because each colour of light has a different wavelength and speed when travelling through a medium other than air.

When white light enters a prism, it slows down and bends or refracts. This is due to a change in speed as light moves from one medium (air) to another (glass). However, not all colours slow down and bend at the same rate. Violet light, which has the shortest wavelength, slows down the most and hence bends the most. On the other hand, red light, with the longest wavelength, slows down the least and bends the least. This difference in bending causes the colours to spread out and form a spectrum, a process known as dispersion.

The phenomenon of light dispersion is not only limited to prisms. It can also be observed in everyday life. For instance, when sunlight passes through raindrops, it results in a natural spectrum of light in the sky, creating a rainbow. Similarly, the sparkling of a diamond is also due to the dispersion of light.

In summary, dispersion of light is a fundamental concept in physics that explains how white light can be separated into different colours. It is a result of the varying speeds and wavelengths of different colours of light when they pass through a medium other than air.