Fig. 9.1 illustrates the electric circuit used for a fan heater. Air is forced past the heater by the fan. A motor, which is connected to a 24 V d.c. supply, drives the fan.
(a)[1]
Explain how an a.c. supply differs from a d.c. supply.
(b(i))[1]
Name the part.
(b(ii))[2]
Explain the role of this component in the circuit.
(c(i))[4]
Calculate the current in the heater. Give the unit.
(c(ii))[1]
Suggest the fuse rating needed for the heater.
(d)[1]
Explain the advantage of earthing the metal case.
Worked solution & mark scheme
This 10-mark question has a full step-by-step worked solution and mark scheme. One marking point: “a.c. current reverses direction OR d.c. only one direction” …