(a)[2]
Define the electric potential at a point in words.
(b(i))[2]
Show that the electric potential $V$ at point P, when $x = 10\,\text{pm}$, is $130\,\text{V}$.
(b(ii))[2]
Calculate, to two significant figures, the value of $V$ when $x = 30\,\text{pm}$.
(b(iii))[1]
On Fig. 5.1, place a cross (\times) at one location, other than infinity, where the electric potential is zero.
(b(iv))[3]
On Fig. 5.2, sketch the way $V$ varies with $x$ from $x = 10\,\text{pm}$ to $x = 110\,\text{pm}$.