Question

What are the conditions to be satisfied for obtaining a pure spectrum using a
prism?​

Answer 1

Pure spectrum

A spectrum in which colours do not overlap like that happens in case of an impure spectrum.

The required condition for obtaining the pure spectrum using prism are as follows:

• Minimum deviation should be there in the position of prism so that chances of mixing is very less.

• Narrow slit should be used for the purpose.

• Rays should have parallel incidents in order to prevent the lights from coinciding with each other.

• Emerging light rays should be focused in a proper manner.

• Always try to ensure that wavelength of the scattering object should be much - much smaller than the actual wavelength of the light.

Note :

minimum two prisms are required for production of a pure spectrum while impure can be produced with a single itself.