(a)[2]
Define electric potential at a point in terms of the work done per unit charge.
(b)[3]
Two isolated charged metal spheres X and Y are placed close together in a vacuum, with their centres separated by $24\,\text{m}$. Point P is at a variable distance $x$ from the centre of sphere X on the line joining the centres of the spheres. Fig. 5.1 shows how the electric potential $V$ at point P varies with $x$ because of the spheres. State three conclusions about the spheres that can be drawn from Fig. 5.1. The conclusions may be qualitative or quantitative.
(c)[3]
A positively charged particle is placed at point P in (b), where $x = 12\,\text{m}$. The particle is then released. Describe and explain the motion that follows.