Components in Series & Parallel Circuits (Edexcel GCSE Physics)

Exam Questions

1 hour8 questions
1a
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2 marks
The graphs in Figure 1 show how the current in a component changes with the voltage applied across the component.

 

Draw a line from each component to its correct graph.

9qLBfB3i_10-2-e-1a-circuit-diagrams-and-graphs
Figure 1
1b
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2 marks

Describe how the resistance of a light-dependent resistor (LDR) varies with light intensity.

1c
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1 mark
Figure 1 shows the symbol for an electrical component.
10-2-e-1c-thermistory-circuit-symbol
Figure 1
 
State the name of the component shown in Figure 1.
1d
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2 marks

Describe how the resistance of a thermistor varies with a change of temperature.

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2a
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4 marks

Ohmic conductors are conductors that have a fixed resistance. 

State which of the following are non-ohmic conductors.

Diode Thermistor Filament lamp LDR Resistor
2b
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1 mark

Which of the following is true?

square   A   If two resistors are in series, their net resistance is decreased

square   B   If two resistors are in parallel, their net resistance in increased

square   C   If two resistors are in series or parallel, their net resistance is increased

square   D   If two resistors are in parallel, their net resistance is decreased

2c
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1 mark

Figure 1 shows how the current varies with a potential difference for a filament lamp.

q3teC-Yz_10-2-e-2c-filament-lamp-example

Figure 1

State what the gradient of the graph represents.

2d
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3 marks

Calculate the resistance of the lamp when the potential difference is 3.0 V.

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3a
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2 marks

Figure 1 shows a series circuit connecting a battery of potential difference 24 V, a filament lamp and a resistor.

10-2-e-3a-series-circuit

Figure 1

Sketch the circuit with the lamp and resistor in parallel instead.

3b
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1 mark

The lamp and resistor have the same resistance.

Determine the potential difference in the lamp and resistor when connected in Figure 1.

3c
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1 mark

State a component that could be added to Figure 1 to change the current in the circuit.

3d
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2 marks

The lamp in Figure 1 is now replaced with an LED to test and measure its output with changing light intensity. 

Sketch the circuit symbol for the LED on Figure 2. 

10-2-e-3d-series-circuit-missing-led

Figure 2

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1a
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8 marks

A student investigates resistors connected in parallel using a number of resistors.

Each resistor has the same resistance.

Figure 19 shows a circuit diagram with one resistor, R.

fig-19-paper2h-june2020-edexcel-gcse-physics

Figure 19

(i)
Add to Figure 19:
  • a voltmeter to find the potential difference across resistor R
  • another resistor in parallel with resistor R.

[2]

(ii)
State the measurements that the student must take to find the overall resistance of the resistors in parallel.

[2]

(iii)
The student investigates how the overall resistance of the circuit changes when additional resistors are added in parallel to R.

Each resistor has the same resistance.
Figure 20 shows the results of the student’s investigation.

fig-20-paper2h-june2020-edexcel-gcse-physicsFigure 20

State the resistance of a single resistor.

[1]

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

(iv)
Comment on the relationship between the overall resistance of the circuit and the number of resistors in parallel.

Use information from Figure 20 to support your answer.

[3]

1b
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4 marks

A different circuit is then set up with two resistors as shown in Figure 21.

fig-21-paper2h-june2020-edexcel-gcse-physics
Figure 21

i)
Calculate the potential difference across the 15 Ω resistor.

[2]

potential difference = .............................................................. V

ii)
Calculate the total power dissipated when there is a current of 0.20 A in the two resistors.
Use the equation

P = I2 × R

[2]

power produced .............................................................. W

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2a5 marks
Figure 18 shows identical filament lamps connected together to a 12V power supply.
fig-18-paper2h-june2018-edexcel-gcse-physics
Figure 18

(i)
Calculate the potential difference across each lamp.

[1]

potential difference = ............................................... V

(ii)
The power output of each lamp is 0.75W

Calculate the resistance of each lamp.

[4]

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

2b6 marks

Explain, with the aid of a circuit diagram, the method a student could use to investigate how the resistance of a single lamp changes with the potential difference across the lamp.

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3a2 marks

A student is investigating the I-V characteristic of a filament bulb. Figure 1 shows the circuit they set up to conduct the investigation.

2-1-h-1a-incorrect-circuit

Figure 1

The circuit shown in Figure 1 will not provide valid results. 

Identify one error the student has made and state how to rectify it.

3b5 marks

The student plotted the graph shown in Figure 2 from her data.

2-1-h-1c-iv-characteristics-filament-graph

Figure 2

Use words from the box to complete the following sentences.

  
increase decrease increases decreases

As the potential difference increases, the current ............................., but the rate at which this occurs .............................This is because the temperature of the filament in the bulb ............................. with current.So the resistance ............................. causing the current to .............................

3c1 mark

Which of the following steps is not a suitable safety procedure for this investigation?

square   A   Keep liquids away from the equipment

square   B   Tie long hair back

square   C   Turn off the power supply if burning is smelled

square   D   Take care when handling the hot filament bulbs

3d4 marks

Use the graph shown in Figure 2 to calculate the resistance of the filament lamp when the potential difference is 3 V.

Give your answer to an appropriate number of significant figures.

2-1-h-1c-iv-characteristics-filament-graph

Figure 2

  

   

resistance of filament lamp = .................................... Ω

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4a1 mark

Draw the circuit symbol for a light-dependent resistor (LDR).

4b1 mark
Which of the following sketch graphs shows the IV characteristic of an LDR?
square  A square  B
graph-a graph-b
   
   
square  C square  D
graph-c graph-d
4c2 marks
Explain how the shape of the graph in part (b) shows that the LDR is an ohmic conductor.
4d1 mark
LDRs are used as light sensors to turn on lights as it gets dark outside.

Describe how the resistance of an LDR varies with light intensity.

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5a4 marks

Some students in a physics class are investigating the I-V characteristics of a fixed resistor.

The students are given the following equipment:

    • An ammeter
    • A voltmeter
    • A variable resistor
    • Fixed resistors of 100 Ω, 200 Ω, 400  and 500 Ω
    • A power pack
    • Wires

Draw a circuit using the equipment from the list that would enable the students to gather valid data.

5b5 marks
Describe a method that would allow the students to obtain valid results.
5c1 mark
The students plotted their data and produced the graph shown in Figure 1.

2-1-m-5c-iv-characteristics-graph

Figure 1

Write down an expression for the gradient of the graph in terms of resistance.

5d4 marks
Use the graph to determine the resistance of the fixed resistor used by the students.

   

   

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

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