(a)[2]
What is meant by electric potential at a point?
(b(i))[2]
A positively charged isolated solid metal sphere has radius $r$. The potential at its surface is $9.0 \times 10^{4}\,\text{V}$. At a point $3r$ from the centre, the electric field strength is $2.0 \times 10^{5}\,\text{N C}^{-1}$. Determine the electric field strength at the surface of the sphere.
(b(ii))[2]
Show that the sphere’s radius is $5.0\,\text{cm}$.
(b(iii))[2]
Calculate the charge carried by the sphere.
(b)
A positively charged isolated solid metal sphere has radius $r$. The potential at its surface is $9.0 \times 10^{4}\,\text{V}$. At a point $3r$ from the centre, the electric field strength is $2.0 \times 10^{5}\,\text{N C}^{-1}$.
(b(iv))[2]
Use your answer from (b)(iii) to find the capacitance of the sphere.