(a(i))[2]
On Fig. 7.1, add six field lines to show the electric field between the metal plates.
(a(ii))[2]
Calculate the electric field strength $E$ for the region between the plates.
(b(i))[2]
A force acts on $A$ because of the electric field between the plates. Show that this force is $4.8 \times 10^{-15}\,\text{N}$.
(b(ii))[3]
The insulating rod connecting $A$ and $B$ is fixed in the position shown in Fig. 7.2. Calculate the torque of the couple acting on the rod.
(b(iii))[2]
The insulating rod is now released so that it can rotate freely about $C$. State and explain the position of the rod when it comes to rest.