A narrow beam of red light, with frequency $4.7 \times 10^{14}\,\text{Hz}$, moves through air at a speed of $3.0 \times 10^8\,\text{m s}^{-1}$. Fig. 4.1 depicts this red light hitting the surface of a parallel-sided glass block. The diagram labels red light and glass block, and it shows angles $45^{\circ}$ and $30^{\circ}$.
(a)[3]
Calculate the wavelength, in air, of this red light.
(b(i))[2]
State how the speed, frequency and wavelength of the light change as it enters the block.
(b(ii))[3]
Using the angles marked on Fig. 4.1, calculate the refractive index of the glass.
(b(iii))[2]
The light continues along the route shown in Fig. 4.1 until it reaches the lower surface of the block. It then leaves into the air. Draw on Fig. 4.1 to show the route followed by the light up to the lower surface and the path taken by the light after it emerges into the air.
Worked solution & mark scheme
This 10-mark question has a full step-by-step worked solution and mark scheme. One marking point: “$\lambda = v / f$, or $3.0 \times 10^8 / 4.7 \times 10^14$” …