4.3.3. Action and use of circuit components
A subsection of Physics, 5054, through 4. Electricity and magnetism
Listing 10 of 34 questions
EITHER shows a circuit that contains a direct current (d.c.) power supply, a light-dependent resistor (LDR), two fixed resistors, M and N, and two ammeters. A A ammeter 2 ammeter 1 M + – N The reading on ammeter 1 is 1.6 mA. Calculate the time taken for a charge of 7.2 C to pass through ammeter 1. time = Some time later, the brightness of the light incident on the LDR decreases. Explain what happens to: the reading on ammeter 2 the time taken for a charge of 7.2 C to pass through ammeter 1. OR shows the symbol for an electronic circuit component. State the name of the component shown in . is the diagram of a circuit that includes this component, a light-dependent resistor (LDR) and a relay. + – M mains supply relay motor 6.0 V The motor in is part of the pump in a garden fountain. In the dark, the pump does not work. In the morning, the brightness of the light incident on the LDR increases. State what happens to the LDR. Explain why the motor switches on.
5054_w21_qp_22
THEORY
2021
Paper 2, Variant 2
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A student connects a battery to two resistors. The circuit diagram is shown in . 10 Ω 40 Ω The potential difference (p.d.) across the 40 Ω resistor is 9.6 V. State what is meant by the potential difference across a resistor. Calculate the current in the 40 Ω resistor. current = Calculate the electromotive force (e.m.f.) of the battery. e.m.f. = The student has three different voltmeters to measure the p.d. across the 40 Ω resistor. These are labelled 0–2 V, 0–20 V and 0–200 V. Each has a pointer that shows the p.d. on a scale. State and explain which of the three voltmeters is best to measure this p.d. Calculate the power P produced in the 10 Ω resistor. P = The student has available two 10 Ω resistors, with power ratings of 2 1P and 2P. Suggest why a resistor with a power rating of 2 1P is not suitable for the circuit in . The student adds a resistor R to the circuit, to make the circuit shown in . 10 Ω R Ω Complete the table in to show what happens as resistor R is connected. You should state whether each quantity increases, decreases or stays the same and give a brief explanation of why any change occurs. Calculations are not required. quantity increases, decreases or stays the same as resistor R is added brief explanation of why the change occurs current in 10 Ω resistor increases p.d. across 10 Ω resistor p.d. across 40 Ω resistor
5054_s18_qp_22
THEORY
2018
Paper 2, Variant 2
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Questions Discovered
34