When a ray of white light falls on a prism, which of the following statements are correct ?

1. The dispersion of white light occurs at the first surface of the prism.
2. The deviation of light rays occurs at both the surfaces of the prism.
3. The prism does not produce colours, but it only splits the various colours present in the white light.
4. All of the above.

The wavelength range of white light is:

1. 4000 nm to 8000 nm
2. 40 nm to 80 nm
3. 400 nm to 800 nm
4. 4 nm to 8 nm

In the spectrum of white light by a prism, the colour at the extreme end opposite to the base of a prism is —

1. violet
2. yellow
3. red
4. blue

Out of red, blue and violet, which colour has the greatest speed in vacuum ?

1. red
2. blue
3. violet
4. all have the same speed