(a) Define:(i) the coulomb; (ii) resistance.

(b) State the three effects of an electric current.

(c) State the standard international colour convention for the insulating material covering the following electrical wires in a three-pin plug: (i) live; (ii) neutral; (iii) earth.

(d) 
A water melon of mass 5.0 kg is suspended on a uniform rod of mass 4.0 kg and 4.0 in long as illustrated in the diagram above. If the rod is in equilibrium by the action of the force between the charges +q and -q, calculate the:

(i) anti-clockwise moment;
(ii) value of q. [ g = 10 ms\(^{-2}\)]