Quelpr
4 marksCapacitors

CAPE Physics Unit 2 · May/June 2026 · Paper 2 · Question 1(e)(iii)

Under certain atmospheric conditions, the air between the cloud and the ground may become partially ionized and begin conducting current, leading to a lightning strike. Table 1 records the exponential decay of the initial charge, Q₀, from the cloud during such a strike.

Determine the slope of the graph in (e) (ii) and state what this value represents.

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

The mark scheme is shown once you've answered.

Practise this question

Other parts of this question

  1. 1(a)Define the term 'capacitance' as it relates to electric circuits.[1 mark]
  2. 1(b)The formula below is used to calculate the capacitance of a parallel plate capacitor: C = εA/d. State the meaning of EACH symbol on the right-hand side of the…[3 marks]
  3. 1(c)Using the formulae to calculate the electric field, E, in a parallel plate capacitor and the charge, Q, on the plates, show that E = (1/ε) * (Q/A).[3 marks]
  4. 1(d)(i)Calculate the capacitance of the system formed by the cloud, air and the ground.[3 marks]
  5. 1(d)(ii)Calculate the energy stored in the cloud-ground capacitor.[3 marks]
  6. 1(d)(iii)Calculate the value of the electric field in the cloud-ground capacitor.[2 marks]
  7. 1(d)(iv)State how the values calculated in (d) (i), (ii) and (iii) will change if the true value of the permittivity of air was used.[3 marks]
  8. 1(e)(i)Complete Columns 3 and 4 of Table 1.[2 marks]
  9. 1(e)(ii)On the grid provided in Figure 1 on page 9, plot a graph of ln (Q/Q₀) versus t. Draw the line of best fit through the points.[4 marks]
  10. 1(e)(iv)Based on the result obtained in (e) (iii), estimate the duration of the lightning strike.[2 marks]

More practice: the rest of this paper · more Capacitors questions · all CAPE Physics Unit 2 past papers