The newest 20 of 244 written questions, plus 47 multiple-choice. Open one to see it on the real paper.
For point P, compare the electric field due to the proton with the electric field due to the electron.
See it on the paper →For point P, compare the electric potential due to the proton with the electric potential due to the electron.
See it on the paper →The elementary charge is e and the permittivity of free space is ¢). State an expression, in terms of x, e and £ ys for the magnitude of the electric force F between the proton and the electron.
See it on the paper →Determine an expression, in terms of F and x, for the electric potential energy E, of the proton and the electron. Ep=. . 11]
See it on the paper →Define electric potential at a point.
See it on the paper →State an expression, in terms of R and Q, for the magnitude V, of the electric potential at the surface of the sphere. Identify any other symbols that you use. Vo=
See it on the paper →On Figure 6.2, sketch the variation of the electric potential V at distance x from the centre of the sphere between x = Rand x = 3R. Vo V 0 0 R 2R 3R x Vy Figure 6.2
See it on the paper →For point P, compare the electric field due to the proton with the electric field due to the electron.
See it on the paper →For point P, compare the electric potential due to the proton with the electric potential due to the electron.
See it on the paper →The elementary charge is e and the permittivity of free space is ¢). State an expression, in terms of x, e and £ ys for the magnitude of the electric force F between the proton and the electron.
See it on the paper →Determine an expression, in terms of F and x, for the electric potential energy E, of the proton and the electron. Ep=. . 11]
See it on the paper →Define electric field at a point.
See it on the paper →On Figure 2.1, draw four field lines to represent the electric field between the plates.
See it on the paper →Explain, with reference to forces, whether the sign of Q is positive or negative.
See it on the paper →the electric field strength E
See it on the paper →the weight W of the droplet.
See it on the paper →The plates in 2(b) have a p.d. across them of 4800V and a separation of 0.024m. The magnitude of the charge on the oil droplet is 3e, where e is the elementary charge. Calculate the mass of the oil droplet.
See it on the paper →The polarity of the p.d. across the plates in 2(b) is reversed. Describe and explain the subsequent motion of the oil droplet.
See it on the paper →Define electric potential at a point.
See it on the paper →Show that the electric potential V at point P when x = 10 pm is equal to 130 V.
See it on the paper →Comprehensive responses • Candidates gave the correct definition of electric field. Limited responses • Candidates realised that electric field strength is the force per unit charge. • Candidates needed to realise that electric field is a vector quantity and that the direction is correctly established by making clear that electric field is force per unit positive charge.
— Examiner report, February/March 2026, 9702/42 Q2(a) (Cambridge)
Comprehensive responses • Candidates gave the correct field line pattern with the field direction correctly indicated. Limited responses • Candidates usually indicated the correct field direction. • Candidates needed to ensure the field lines were straight and perpendicular to the plates. • Candidates needed to make sure the lines extended all the way from plate to plate. • Candidates needed to s...
— Examiner report, February/March 2026, 9702/42 Q2(b)(i) (Cambridge)
Comprehensive responses • Candidates clearly described the correct directions for the gravitational and electric forces. • Candidates correctly related the direction of the electric force to the positive sign of the charge. Limited responses • Candidates often drew the correct conclusion with some supportive reasoning. • Candidates needed to be clearer in naming the two relevant forces.
— Examiner report, February/March 2026, 9702/42 Q2(b)(ii) (Cambridge)
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