A student finds the refractive index of the material of a transparent block ABCD by following the route of a light ray through it.
The setup is illustrated in Fig. 3.1.
(a(i))[1]
On Fig. 3.1, construct a normal to side AB at point Q. Keep extending the normal until it reaches side CD. Mark the point where the normal cuts CD with the letter R.
(a(ii))[1]
Find the angle of incidence $\alpha$ of ray PQ on side AB.
(b(i))[1]
Find the length $x$ of QS.
(b(ii))[2]
Find the length $y$ of ST.
(c)[1]
The refractive index $n$ of the material of the block is given by the equation $n = \frac{x}{y}$. Calculate $n$.
Worked solution & mark scheme
This 6-mark question has a full step-by-step worked solution and mark scheme. One marking point: “A normal has been drawn at point Q and extended to meet CD, with point R labelled” …