(a(i))[1]
On Fig. 4.1, show and label the angle of incidence $i$ and the angle of refraction $r$ for the blue light as it enters the prism.
(a(ii))[1]
On Fig. 4.1, extend the blue light ray after it hits the left side of the prism.
(a(iii))[2]
On Fig. 4.1, draw the path of the red light as it moves through the prism and after it strikes the left side of the prism.
(b(i))[2]
State what the critical angle means.
(b(ii))[2]
Glass has a refractive index of $1.5$ for blue light. Calculate the critical angle $c$ for blue light in glass. Show your working.