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3 marksParticulate Nature of Electromagnetic Radiation

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

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.

On the axes provided in Figure 7 on page 19, plot a graph of stopping potential, V_s, versus frequency, f. Draw the line of best fit through the points.

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Other parts of this question

  1. 3(a)(i)Identify the components labelled A, B, C and state the role of EACH component identified.[6 marks]
  2. 3(a)(ii)Define the term 'stopping potential'.[2 marks]
  3. 3(b)(i)Using the equation f = c/λ, complete Column 3 of Table 2.[2 marks]
  4. 3(b)(iii)Use the graph in (b) (ii) to determine the threshold wavelength for the material of the photosensitive emitting plate.[3 marks]
  5. 3(b)(iv)Explain what is meant by the 'work function of a material'.[2 marks]
  6. 3(b)(v)Calculate the maximum velocity of the ejected photoelectrons.[6 marks]
  7. 3(b)(vi)Calculate the slope of the graph in (b) (ii) and use it to determine a value for Planck's constant.[6 marks]

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