Physics 9702 · AS & A Level · Electric potential

Electric potential — practice question

A charged metal sphere is placed alone in space. The electric potential $V$ is measured at a range of distances $x$ from the centre of the sphere. Fig. 5.1 shows how the potential $V$ changes with distance $x$.
(a)[3]

Use Fig. 5.1 to find the electric field strength, in $\text{N C}^{-1}$, at the position where $x = 4.0\,\text{cm}$. Show your working.

(b(i))[1]

The charge on the sphere is $8.0 \times 10^{-9}\,\text{C}$. Use Fig. 5.1 to state the electric potential at the surface of the sphere.

(b(ii))[2]

The sphere behaves as a capacitor. Determine the capacitance of the sphere.

(ii)[2]

The sphere behaves as a capacitor. Determine the capacitance of the sphere.

Worked solution & mark scheme

This 8-mark question has a full step-by-step worked solution and mark scheme. One marking point: Electric field strength is equal to the potential gradient

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