Concept:Angular dispersion is the angular separation of the different colours in white light after they pass through a prism.
It arises because each colour has a different wavelength and experiences a different refractive index in the prism.
Explanation:When white light enters a prism, each colour is bent by a different amount because the refractive index of the prism is not the same for all wavelengths.
For a given colour, the actual deviation produced by the prism also depends on the angle at which the light strikes the prism.
This means the total angular spread between the violet and red rays depends on both the refractive index of the material and the angle of incidence.
The thickness of the prism does not directly control the angular separation of the colours.
A wider or narrower prism does not change the basic dispersive effect once the refracting angle is fixed.
So the correct condition must include both the wavelength-dependent property and the geometry of the incident ray.
Answer:Option B — the angle of incidence as well as the index of refraction.