Question

What is a spectrum? Why do different coloured rays deviate differently on passing through a glass prism?(All India - 2011)

Answer 1

Answer:

spectrum is the combination of 7 colours of white light when it deviate through a glass prism. colours are Vibgyor.

Answer 2

Answer to both questions are given below -

Spectrum is constituent set of colors which light ray contains.

Refractive index of prism is greater than air.

This means while emerging out, light rays travel from denser medium to rarer medium, and according to rule they deviate aways from the normal.

Therefore the deviation occurs.

Different light rays deviate differently due to their different wavelengths.

Incoming light rays into prism move from rarer to denser medium and hence deviate towards the normal.