Question

In the case of dispersion without deviation why is the net dispersion=theta 1 + theta 2?My logic is that as the two prisms are kept in the opposite sense they are dispersing it in the opposite direction i.e. when the white light goes through the first prism the violet light is deviated the most towards the base of the prism then when the light enters the second prism the violet light is deviated upwards(which is in the opposite sense) this the angular dispersion is in the opposite sense in first and the second prism and the net dispersion should be =theta 1-theta 2

Answer 1