(a)[2]
Define electric potential at a point in an electric field.
(b)
An isolated solid metal sphere has a positive charge. The change in potential $V$ with distance $x$ from the centre of the sphere is plotted in Fig. 5.1. Use Fig. 5.1 to suggest:
(b(i))[1]
why the sphere’s radius cannot exceed $1.0\,\text{cm}$.
(b(ii))[3]
that the sphere’s charge behaves as though it were a point charge.
(c)[2]
If you assume the sphere’s charge behaves as a point charge, use the information in Fig. 5.1 to determine the charge on the sphere.
(ii)[3]
that the charge on the sphere acts as if it were a point charge.