Fig. 7.1 shows a circuit diagram containing component X. The diagram includes a battery, a switch, an ammeter, a $20\,\Omega$ resistor, a $30\,\Omega$ resistor, and component X.
(a)[1]
State what component X is called.
(b(i))[1]
State an equation linking $V_X$ with $V_{30}$.
(b(ii))[1]
State an equation linking $V_X$ with $E$ and $V_{20}$.
(c(i))[3]
Calculate the resistance of the circuit in total.
(c(ii))[2]
Calculate the reading on the ammeter.
(d)[2]
State and explain the change in the ammeter reading.
Worked solution & mark scheme
This 10-mark question has a full step-by-step worked solution and mark scheme. One marking point: “A thermistor (c.a.o.)” …