(a)[1]
Define the electric field at a point.
(b(i))[2]
On Fig. 6.1, draw field lines to show the electric field outside the sphere caused by the charge on the sphere.
(b(ii))[2]
Calculate the electric potential at the surface of the sphere.
(b(iii))[2]
Determine the sphere’s radius.
(b(iv))[2]
Calculate the electric field strength $E$ at the surface of the sphere. Include a unit in your answer.
(c)[2]
The sphere in (b) is discharged by connecting it to earth $(0\,\text{V})$ through a resistor of resistance $120\,\text{M}\Omega$. Calculate the time for the charge to decrease to $26\,\text{pC}$.