Physics 5054 · O Level · Action and use of circuit components
Action and use of circuit components — practice question
A potential divider is formed using a light-dependent resistor (LDR) together with a $6.0\,\text{k}\Omega$ fixed resistor. This potential divider is placed in series with a 12 V d.c. power supply, and a voltmeter is placed across the $6.0\,\text{k}\Omega$ resistor. Fig. 8.1 shows the circuit diagram.
Light falls on the LDR. The resistance of the LDR is $2.0\,\text{k}\Omega$.
(a(i))[2]
Calculate the current flowing in the LDR.
(a(ii))[1]
Calculate the voltmeter reading.
(b)[2]
The brightness of the light on the LDR is increased gradually. State and explain what happens to the reading on the voltmeter.
(c)[1]
Suggest a use for a potential divider made from an LDR and a fixed resistor.
Worked solution & mark scheme
This 6-mark question has a full step-by-step worked solution and mark scheme.