AQA GCSE Physics

Topic Questions

2.2 Series & Parallel Circuits

1a2 marks
Explain what is meant by the term A.C.
1b1 mark

Which graph shows a direct current?

Tick (✓) one box.

 

2-2-e-1b-distractor-graph 

1c1 mark

What is the potential difference of the UK mains supply?

Tick (✓) one box.   

250 V begin mathsize 36px style square end style
330 V size 36px square
50 V size 36px square
230 V size 36px square

1d1 mark

What is the frequency of the UK mains supply?

Tick (✓) one box.

   

230 V begin mathsize 36px style square end style
230 Hz size 36px square
50 V size 36px square
50 Hz  size 36px square
100 A size 36px square

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2a1 mark

Figure 1 shows a circuit with five ammeters.

Figure 1

2-2-e-2a-circuit-5-ammeters

State whether this circuit is a series circuit or a parallel circuit.
2b2 marks

Complete the sentences. 

Choose answers from the box. 

Each answer can be used once, more than once or not at all.

potential difference

series

parallel charge

     

Ammeters need to be positioned in .............................. within a circuit.

This is because the ammeter measures the amount of .............................. flowing through it per second.

  

2c3 marks

The lamps in Figure 1 are identical.

Figure 1

circuit-5-ammeters

Ammeter 1 reads 0.33 A

Ammeter 2 reads 0.11 A

Complete Table 1 by filling in the missing values for ammeters 3, 4 and 5.

Table 1
Ammeter 1 Ammeter 2 Ammeter 3 Ammeter 4 Ammeter 5
0.33 A 0.11 A      
2d5 marks

The potential difference across the power supply in Figure 1 is 6 V.

Calculate the resistance of each bulb.

   

Resistance = .................................... Ω

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3a2 marks

A student sets up the following equipment as shown in Figure 1.

Figure 1

2-2-e-3a-circuit-variable-resistor

Add an ammeter and a voltmeter in suitable positions to measure the current and potential difference in relation to the bulb.
3b1 mark

Figure 2 shows the reading on the ammeter.

Figure 2

2-2-e-3b-ammeter-reading

Write the value of the ammeter reading.

3c1 mark
State the resolution of the ammeter in Figure 2.
3d3 marks

Complete the sentences. 

Choose answers from the box. 

Each answer can be used once, more than once, or not at all.

series parallel

     

Lamps placed in .............................. will be brighter than lamps placed in ..............................

This is because the resistance in the circuit is greater when the lamps are placed in .............................. 

The energy transferred from the cell to the lamps is greater when the lamps are placed in .............................. 

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4a1 mark

What colour is the insulating cable of the live wire in a UK plug?

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Blue begin mathsize 36px style square end style
Brown size 36px square
Red size 36px square
Yellow and green stripes size 36px square

4b1 mark
(b)

What is the function of the earth wire?

Tick (✓) one box.

Carries the current to the circuit begin mathsize 36px style square end style
Completes the circuit square
Stops the appliance becoming live  square

[1 mark]

4c3 marks

Complete the sentences. 

Choose answers from the box. 

Each answer can be used once, more than once or not at all.

close to 0 V 0 V 230 V

     

The potential difference of the live wire is ..............................

The potential difference of the neutral wire is ..............................

The potential difference of the earth wire is .............................. 

4d3 marks

The earth wire provides a low resistance path to the Earth where a surge in current can be safely diverted away from the appliance. The circuit will also contain a fuse.

Explain the purpose of a fuse.

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5a2 marks

Figure 1 shows three resistors placed in series.

Figure 1

2-2-e-5a-circuit-resistors-series

Determine the total resistance of the circuit.   
Total resistance = .................................... Ω
5b1 mark

State how the total resistance would change if the resistors were placed in parallel.

5c3 marks

The 15 Ω resistor was replaced by a fixed resistor with an unknown value. Figure 2 shows the new circuit.

Figure 2

2-2-e-5c-circuit-resistors-series-fig-2

Describe a way to determine the resistance of the new resistor.

 

5d4 marks

A reading of current = 0.065 A was taken from the circuit in Figure 2.

The cell has a potential difference of 3 V.

Calculate the resistance of the unknown resistor.

Unknown resistance = .................................... Ω

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1a1 mark

Figure 6 shows a fixed resistor connected in series with a variable resistor.

Figure 6

fig-6-2-2-medium-aqa-gcse-physics

The resistance of the variable resistor can be varied between 100Ω  and 800Ω .

When the variable resistor is set to 100 Ω, voltmeter 1 reads 12 V and voltmeter 2 reads 3 V.

Calculate the potential difference of the battery.
1b2 marks
Determine the resistance of the fixed resistor R in the circuit shown in Figure 6.
1c1 mark
Add an ammeter to Figure 6 above to show how the current through the circuit could be measured.

1d3 marks
Calculate the current through the circuit when the resistance of the variable resistor is set to 400 Ω.

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2a2 marks

A student investigated how the total resistance of a circuit varied with resistors placed in parallel.

Figure 1 shows the circuit the student used.

Figure 1

2-2-h-2a-parallel-resistors-circuit-1

The resistance of each resistor is identical.

The student used an ohmmeter to measure the total resistance.

The student took multiple readings and calculated a mean.

Table 1 shows their results.

Table 1

Number of resistors Total resistance in ohms
Reading 1 Reading 2 Reading 3 Mean
3 17.4 17.9 X 17.7
 

Determine the missing value X for Reading 3.

2b2 marks
Explain how calculating a mean increases the accuracy of the data.
2c3 marks
The student took a fourth reading.

Reading 4 = 15.2 Ω

The student's partner said that Reading 4 should not be included in the mean.

State whether you agree, and explain your answer.

2d2 marks
The student plotted a graph of the data they produced in their investigation. Figure 2 shows the graph.

 

Figure 2

2-2-h-2d-parallel-resistors-graph

Use the graph in Figure 2 to identify the relationship between the mean total resistance and the number of resistors in parallel.

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3a1 mark

A homeowner is completing renovations on their property.

They install a security light that switches on automatically when it gets dark.

Figure 1 shows the circuit for the security light.

Figure 1
2-2-h-3a-ldr-light-circuit

What happens to the resistance of the LDR, and what happens to the current in the circuit when it gets dark?


Tick (✓) one box.

Resistance increases, current increases  begin mathsize 36px style square end style
Resistance increases, current decreases  size 36px square
Resistance decreases, current increases  size 36px square
Resistance decreases, current decreases  size 36px square
3b4 marks

The homeowner also installs a hob in the kitchen. Figure 2 shows the circuit for the hob.


Figure 2

2-2-h-3b-hob-circuit

Explain the benefits of connecting the heating elements in parallel.

3c2 marks
When the electric hob has all four heating elements in use at full power, the maximum current drawn from the mains supply is 27 A.

Table 1 shows the maximum current that can flow safely through copper wires with varying cross-sectional areas.

Table 1

Cross-sectional area (mm2) Maximum current (A)
1.0 11.0
2.5 20.5
4.0 26.0
6.0 33.5

 

Household power sockets are fitted with copper cables with a cross-sectional area of 2.5 mm2.

Explain why it would not be safe to plug the hob into a standard power socket.

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4a2 marks

Figure 1 shows a circuit constructed by a student.


Figure 1

2-2-h-4a-current-ammeter-circuit

Determine the readings on ammeters A2 and A3.

   

   

A2 = .................................... A
 
 
A3 = .................................... A
4b2 marks

Figure 2 shows another circuit the student built.


Figure 2

2-2-h-4b-circuit-ammeter-voltmeter

Determine the reading on the ammeter and voltmeter.

   

   

Ammeter = .................................... A
 
 
Voltmeter = .................................... V
4c3 marks

Figure 3 shows another circuit constructed by the student.


Figure 3

2-2-h-4c-circuit-problem

Determine the resistance of resistor Z.

   

   

Resistance = .................................... Ω

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5a4 marks

A homeowner employs an electrician to install a new shower.

The homeowner chooses to use an electrician rather than doing it himself because if he touches the live wire he will receive an electric shock.

Explain why touching the live wire would cause an electric shock.

5b4 marks

Some electrical appliances are fitted with an earth wire.

Describe how an earth wire acts as a safety feature

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1a2 marks

The circuit in Figure 1 shows how an LDR can be used to turn on a circuit when it gets dark.


Figure 1

fig-1-2-2-medium-aqa-gcse-physics

If the light intensity decreases, what happens to the current and the potential difference across the LDR?

1b2 marks

When the potential difference across the LDR is 3 V, what is its resistance?

Explain your answer.

1c4 marks

When the light gets dimmer, the resistance of the LDR becomes 1000 straight capital omega.

Calculate the current through the LDR when its resistance is 1000straight capital omega.

Give your answer to 3 significant figures.

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2a2 marks

A student has four resistors.

Each resistor has a resistance of 100straight capital omega.

Explain how the resistors should be connected so that the total resistance is as low as possible.
2b3 marks

The four resistors are connected in series with a 3 V cell, as shown in Figure 2 below.

Figure 2

fig-2-2-2-medium-aqa-gcse-physics

Calculate the current that flows through the cell.

Give your answer to 3 significant figures.

2c2 marks
Add an ammeter to Figure 2 which would allow the current through the cell to be measured.

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3a2 marks

A student set up the circuit in Figure 3 below.

Figure 3

fig-3-2-2-medium-aqa-gcse-physics

The ammeter displays a reading of 0.075 A.

Calculate the potential difference across the 80 straight capital omega resistor.

3b3 marks
Calculate the resistance of resistor R in Figure 3.

3c2 marks

Switch X is closed.

State what will happen to the total resistance of the circuit and the current through the circuit.

3d3 marks
Calculate the new current through the circuit.

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4a1 mark

The circuit diagram in Figure 8 shows two resistors connected in parallel.

Figure 8

fig-8-2-2-medium-aqa-gcse-physics

Reading on ammeter A1 = 3 A

Reading on ammeter A2 = 1 A

Using the circuit diagram in Figure 8, answer the questions below:

What is the potential difference across resistor R1?
4b2 marks
Calculate the resistance of resistor R1.
4c1 mark
What is the current flowing through the variable resistor R2?
4d1 mark
Calculate the resistance of the variable resistor R2.
4e3 marks

The resistance of the variable resistor R2 is increased.

What would happen to:

  • The current through R2
  • The potential difference across R2
  • The current through the battery?

Tick (✓) three boxes

  Increase Stay the same Decrease
Current through R2      
potential difference across R2      
current through the battery      

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5a2 marks

Figure 4 below shows how two resistors can be connected in series or in parallel to a 12 V cell.

The resistors are identical.

Figure 4

fig-4-2-2-medium-aqa-gcse-physics

Calculate the potential difference across each resistor when the lamps are connected in series and in parallel.
5b1 mark
Give one disadvantage of connecting the lamps in series rather than in parallel.
5c1 mark

Figure 5 shows how an ammeter can be used to measure the current flowing through the battery for the same circuit.

Figure 5

fig-5-2-2-medium-aqa-gcse-physics

The reading on the ammeter is 1.6 A.

Add an ammeter to Figure 5 to show how to measure the current through resistor R2
5d1 mark

The resistors are identical.

State the current through resistor R2.

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