(a)[1]
Measure the angle of incidence $i$ for the ray at point X on the prism.
(b(i))[1]
At $X$, the angle of refraction is $19^{\circ}$. On Fig. 2.1, draw the refracted ray within the prism.
(b(ii))[1]
Put the letter Y at the point where the refracted ray leaves the prism. Draw the normal at point Y.
(c)[1]
The ray leaves the prism at Y. Explain how the student can record the path of the emergent ray accurately on the paper.