EITHER Fig. 5.1 presents a circuit that includes a direct current (d.c.) power supply, a light-dependent resistor (LDR), two fixed resistors, M and N, together with two ammeters. OR Fig. 5.2 gives the symbol for an electronic circuit component, and Fig. 5.3 displays a circuit containing this component, an LDR and a relay.
(a)[2]
Ammeter 1 reads $1.6\,\text{mA}$. Calculate how long it takes for a charge of $7.2\,\text{C}$ to go through ammeter 1.
(b(i))[1]
Later, the brightness of the light falling on the LDR decreases. Explain what happens to the reading on ammeter 2.
(b(ii))[2]
Explain what happens to the time taken for a charge of $7.2\,\text{C}$ to go through ammeter 1.
(OR-a)[1]
State the name of the component shown in Fig. 5.2.
(OR-b(i))[1]
In the morning, the brightness of the light incident on the LDR increases. State what happens to the LDR.
(OR-b(ii))[3]
Explain why the motor switches on.
Worked solution & mark scheme
This 10-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Therefore, t = Q / I = 7.2 / 0.0016” …