2.1 Circuit symbols and diagrams
9 exam questions worth 17 marks. Write your answer, open the mark scheme, then give yourself the marks you earned. Your answers are saved on this device.
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Which component is used to measure the current in a circuit?
Choose one answer.
Correct Not quite: the answer is Ammeter
Mark scheme
B: ammeter
Model answer
Ammeter (B).
State the difference between a cell and a battery.
Mark scheme
a battery is two or more cells (connected together) / a cell is a single one
Model answer
A battery is made of two or more cells joined together, while a cell is a single unit.
A student wants to measure the current through a lamp and the potential difference across it. State how the ammeter and the voltmeter must be connected.
Mark scheme
ammeter in series with the lamp (1); voltmeter in parallel with / across the lamp (1)
Model answer
The ammeter is connected in series with the lamp. The voltmeter is connected in parallel, across the lamp.
Name the component that allows current to pass in one direction only, and the component whose resistance falls as the light gets brighter.
Mark scheme
diode (1); LDR / light-dependent resistor (1)
Model answer
A diode allows current in one direction only. An LDR (light-dependent resistor) has a resistance that falls as the light gets brighter.
Explain why a lamp in a circuit does not light when the switch is open.
Mark scheme
the open switch makes a gap in the circuit / the circuit is not a complete loop (1); so charge cannot flow / there is no current (1)
Model answer
An open switch leaves a gap, so the circuit is not a complete loop. Charge cannot flow, so there is no current and the lamp stays off.
Describe how to draw the circuit diagram for a cell, a closed switch and a lamp in series, with an ammeter in the loop and a voltmeter across the lamp.
Mark scheme
all components drawn with the correct standard symbols (1); components, including the ammeter, joined in one complete series loop with straight lines and no gaps (1); voltmeter on a separate branch connected in parallel across the lamp (1)
Model answer
Draw one closed loop of straight wires containing the cell, the closed switch, the lamp and the ammeter, each with its standard symbol. Then add the voltmeter symbol on a separate branch joined to the wires either side of the lamp, so it is in parallel with the lamp.
Which line in the symbol for a cell represents the positive terminal?
Choose one answer.
Correct Not quite: the answer is The longer, thinner line
Mark scheme
B: The longer, thinner line
Model answer
The longer, thinner line (B).
A student connects a cell, a switch, a lamp and some wires in a series circuit. The switch is closed but the lamp does not light. Suggest three possible reasons.
Mark scheme
any three from: a break / loose connection in the wire (1); the cell is flat / connected the wrong way (1); the lamp filament has broken / the bulb has blown (1); the switch is faulty / not making contact (1)
Model answer
The wire might be broken or a connection loose, the lamp might have blown, or the cell may be flat.
A fuse is connected in series with an appliance. Explain why it is not connected in parallel.
Mark scheme
a fuse must carry the whole current to the appliance (1); in parallel only part of the current would go through it, so it would not melt to protect the appliance / the circuit would not be broken (1)
Model answer
The fuse has to carry the whole of the current that flows to the appliance, so that it melts if the current is too big. In parallel, only part of the current would pass through it.
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