(a(i))[1]
draw the path taken by the refracted ray in the air
(a(ii))[1]
mark the angle of incidence, and label it with the letter $i$
(a(iii))[1]
mark the angle of refraction, and label it with the letter $r$.
(b)[2]
State what happens to the ray at X and explain why this occurs.
(c(i))[2]
Complete the sentences to compare their speed and frequency. The speed of visible light is ............................................. the speed of X-rays. The frequency of visible light is ............................................. the frequency of X-rays.
(c(ii))[1]
Describe one application of X-rays.