CAPE Physics Unit 2 · May/June 2026 · Paper 2 · Question 3(b)(iii)

In a photoelectric emission experiment using the apparatus in Figure 6, the potential difference between the electrodes is adjusted until it reaches the stopping potential, V_s. The incident wavelength, λ, is varied and corresponding values of stopping potential are recorded. The results of the experiment are recorded in Table 2.

Use the graph in (b) (ii) to determine the threshold wavelength for the material of the photosensitive emitting plate.

This question uses a figure or table from the paper — you'll see it when you practise.