Electric potential: past paper questions
Real questions on electric potential
The newest 20 of 112 written questions. Open one to see it on the real paper.
- 9702/41 · October/November 2025 · Q5a[2]
Define electric potential at a point.
See it on the paper → - 9702/41 · October/November 2025 · Q5b(i)[2]
Show that the electric potential V at point P when x = 10 pm is equal to 130 V.
See it on the paper → - 9702/41 · October/November 2025 · Q5b(ii)[2]
Calculate, to two significant figures, V when x = 30 pm. V = V
See it on the paper → - 9702/41 · October/November 2025 · Q5b(iii)[1]
On Fig. 5.1, draw a cross (×) at one position, other than infinity, where the electric potential is zero.
See it on the paper → - 9702/41 · October/November 2025 · Q5b(iv)[3]
On Fig. 5.2, sketch the variation of V with x between x = 10 pm and x = 110 pm. 160 V / V 80 0 10 30 50 70 90 x / pm 110 –80 –160
See it on the paper → - 9702/42 · October/November 2025 · Q6b(ii)[2]
Calculate the electric potential at the surface of the sphere. electric potential = V
See it on the paper → - 9702/42 · October/November 2025 · Q6b(iii)[2]
Determine the radius of the sphere. radius = m
See it on the paper → - 9702/42 · October/November 2025 · Q6b(iv)[2]
Calculate the electric field strength E at the surface of the sphere. Give a unit with your answer. E = unit
See it on the paper → - 9702/42 · October/November 2025 · Q6c[2]
The sphere in (b) is discharged by connecting it to earth (0 V) through a resistor of resistance 120 MΩ. Calculate the time taken for the charge to fall to 26 pC. time = s
See it on the paper → - 9702/43 · October/November 2025 · Q5a[2]
Define electric potential at a point.
See it on the paper → - 9702/43 · October/November 2025 · Q5b(i)[2]
Show that the electric potential V at point P when x = 10 pm is equal to 130 V.
See it on the paper → - 9702/43 · October/November 2025 · Q5b(ii)[2]
Calculate, to two significant figures, V when x = 30 pm. V = V
See it on the paper → - 9702/43 · October/November 2025 · Q5b(iii)[1]
On Fig. 5.1, draw a cross (×) at one position, other than infinity, where the electric potential is zero.
See it on the paper → - 9702/43 · October/November 2025 · Q5b(iv)[3]
On Fig. 5.2, sketch the variation of V with x between x = 10 pm and x = 110 pm. 160 V / V 80 0 10 30 50 70 90 x / pm 110 –80 –160
See it on the paper → - 9702/41 · May/June 2025 · Q2a[2]
State Coulomb’s law.
See it on the paper → - 9702/42 · February/March 2025 · Q2c[2]
The electric potential difference (p.d.) between two parallel plates is V, as shown in Fig. 2.3. +V Fig. 2.3 The distance between the plates is d. The region between the plates is a vacuum. On Fig. 2.4, sketch the variation of the electric potential with distance from the positive plate. V electric potential d 0 distan...
See it on the paper → - 9702/41 · October/November 2024 · Q5a[2]
State the relationship between electric field and electric potential.
See it on the paper → - 9702/41 · October/November 2024 · Q5b[3]
Two charged isolated insulating spheres X and Y are near to each other, as shown in Fig. 5.1. Y X P Fig. 5.1 P is a point on the line joining the centres of the spheres. Explain why it is not possible for the total electric potential and the resultant electric field to simultaneously be zero at point P.
See it on the paper → - 9702/41 · October/November 2024 · Q5c(i)[2]
Show that the distance y of point P from the centre of sphere Y is equal to 2x.
See it on the paper → - 9702/41 · October/November 2024 · Q5c(ii)[1]
State an expression, in terms of Q, x and the permittivity of free space ε 0 , for the electric field strength E X at P due to sphere X. E X =
See it on the paper →
What examiners said
This question required candidates to realise two things. One, that the potential is zero at the earthed plate and +V at the upper plate. Two, that the electric field between parallel plates is uniform. Candidates who realised both aspects, and took care over the start and end points of their line, were generally able to achieve the marks.
— Examiner report, February/March 2025, 9702/42 Q2(c) (Cambridge)
There were many correct similarities and differences stated here. Some candidates gave responses that were correct for forces or fields rather than potentials, such as “both are inversely proportional to distance squared” or “one is attractive and the other is repulsive”.
— Examiner report, May/June 2023, 9702/41 Q1(a)(iii) (Cambridge)
This proof proved to be challenging for many candidates. A significant number of candidates started with the definition of electric field strength as F / Q which is correct, but they needed to extend it to the field due to a point charge. Some candidates were attempted to equate the two field strengths, when they have different dimensions so cannot be equated.
— Examiner report, May/June 2023, 9702/41 Q1(b)(i) (Cambridge)
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