Observation

The expected answers were;

(a)       Advantages of hydroelectric over thermal station:
            (i)It incurs no losses when idle.
            (ii)It can start and take up load quickly
            (iii)Low running cost                                        
            (iv)Low maintenance cost

(b)       The mixture of air and fuel is ignited in the combustion chamber. The resulting hot gases in the confined chamber develop a high pressure. The high pressure is directed against the turbine blades to turn the turbine which in turn, turns the generator or alternator through the shaft.

Many candidates who attempted this question could not do it well.