Physics 9702 · AS & A Level · Electric field of a point charge
Electric field of a point charge — practice question
A metal sphere with radius $R$ is isolated in space. Point $P$ lies a distance $x$ from the sphere’s centre, as shown in Fig. 7.1. Fig. 7.2 shows how the electric field strength $E$ produced by the sphere’s charge changes with distance $x$.
(a)[2]
What is the meaning of electric field strength?
(b(i))[2]
From Fig. 7.2, find the radius $R$ of the sphere. Show your working.
(b(ii))[3]
Use Fig. 7.2 to find the charge $Q$ on the sphere.
(c)[3]
An $\alpha$-particle is located $8.0\,\text{cm}$ from the sphere’s centre. Calculate the acceleration of the $\alpha$-particle.
Worked solution & mark scheme
This 10-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Force acting on unit charge” …