A prism splits up a beam of white light into seven colours because _____ is different for different colour.

After tracing the path of a ray of light through a glass prism a student marked the angle of incidence $\left(\angle i\right)$, angle of refraction $\left(\angle r\right)$, angle of emergence $\left(\angle e\right)$ and angle of deviation $\left(\angle D\right)$ as shown in the diagram. The correctly marked angles are:

Study the following figure in which a student has marked the angle of incidence $\angle i$, angle of refraction $\angle r$, angle of emergence $\angle e$, angle of prism $\angle A$ and angle of deviation $\angle D$. The correctly marked angles are 

In the following diagram the correctly marked angles are: