GCSEPhysics: Combined ScienceEdexcelExam Questions3. Conservation of Energy3.2 Efficiency & Energy Resources

Efficiency & Energy Resources (Edexcel GCSE Physics: Combined Science)

Exam Questions

1 hour8 questions
Easy
Medium
1a
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State the equation linking useful energy transfer output, total input energy transfer, and efficiency.

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1b
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60 J of energy is transferred from a cell to a lamp.

16 J is transferred from the lamp to the thermal store of the surroundings. 

State the amount of energy that is usefully transferred.

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1c
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Calculate the efficiency of the lamp. 

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1d
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A student measures the energy transferred to a motor and the energy output by the motor. 

The student says to the class that the motor has an efficiency of 1.5. Another student politely explains that this can't be correct.

Explain how the second student knows the first student's answer is incorrect.

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2a
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Define the term "renewable" in the context of energy resources.

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2b
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Name two types of renewable energy resources.

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2c
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Name two types of non-renewable energy resource.

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2d
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Explain why wind farms are not a reliable energy resource.

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3a
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Name the three main uses of energy resources.

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3b
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Higher Only

Cars use energy from the chemical store in fossil fuels to move around. 

Some energy is dissipated in the wheels of a car. 

Suggest a method to increase the efficiency of these moving parts.

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3c
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Higher Only

Other than friction, name two factors that could be reducing the efficiency of the car. 

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1a5 marks
Figure 13 shows wind turbines, used to generate electricity for the National Grid.

fig-13-paper1h-oct2021-edexcel-gcse-physics
Figure 13

The wind turns the turbine blades.
The wind is a renewable source of energy.

i)
State two other renewable sources of energy.

[2]


1...........................................................................................................................................................

2...........................................................................................................................................................

ii)
For one turbine

• the energy input per second from the wind is 6.2 kJ
• the energy output per second to the National Grid is 2.2 kJ.

Calculate the efficiency of this turbine.

[2]

efficiency = ............................................................

iii)
Suggest a reason why it is impossible for the turbine to use all the kinetic energy of the wind.

[1]

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1b6 marks
Nuclear fission and nuclear fusion are two non-renewable sources of energy.


Compare nuclear fission and nuclear fusion as possible sources of energy for generating electricity using a nuclear reactor.

Your comparison should refer to


• the differences between nuclear fission and nuclear fusion
• the relative advantages and difficulties involved in using these sources.



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2a6 marks
Figure 2 shows an energy transfer diagram for a steam engine.


The diagram shows the amounts of energy transferred each second by the steam engine.  

fig-2-paper1f-june2019-edexcel-gcse-physics
Figure 2

i)
Calculate the amount of wasted energy. 

[1]

wasted energy = ..................... J

ii)
Calculate the efficiency of the steam engine.

Use the equation 
efficiency space equals space fraction numerator open parentheses useful space energy space transferred space by space the space steam space engine close parentheses over denominator open parentheses total space energy space supplied space to space the space steam space engine close parentheses end fraction

[2]

efficiency = ............................

iii)
State what happens to the wasted energy.  

[1]

iv)
Coal is a fossil fuel that is burnt in some steam engines.

State two ways that the use of coal might be harmful to the environment. 

[2]

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2b3 marks

A model train has a mass of 8.0 kg.It travels at a speed of 1.5 m/s.

Calculate the kinetic energy of the model train.

Use the equation

kinetic space energy equals begin inline style bevelled 1 half end style cross times mass space cross times open parentheses speed close parentheses squared

kinetic energy = ................. J

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3a2 marks
State two non‐renewable energy sources.

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3b3 marks
Figure 9 shows the renewable energy sources used in the UK in 2015.

Figure 9 is to scale.
zsZOk82N_fig9-paper1f-june2018-edexcel-gcse-physics
Figure 9

i)
State the energy source that gave the greatest amount of renewable energy for the UK in 2015.

[1]

ii)
Justify your choice of energy source in part (i).

[1]

iii)
State which of these energy sources gave about 20% of the energy from renewable sources for the UK in 2015.

[1]

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3c4 marks
Figure 10 shows all the energy sources used in Canada in 2014 and a prediction for 2040.

9DJtqLMo_fig-10-paper1f-june2018-edexcel-gcse-physics

Figure 10

Discuss the effects on the environment of two predicted changes between 2014 and 2040.

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3d2 marks
Figure 11 shows a wind turbine.

1ZOWNbwc_fig-11-paper1f-june2018-edexcel-gcse-physics

Figure 11

Explain how unwanted energy transfer could be reduced in the gear box.

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4a2 marks

The electrical power demand of the UK at any given time is at least 3 space cross times space 10 to the power of 10 space straight W.

An average gas-fired power station has a power output of 8.75 space cross times space 10 to the power of 8 space straight W.

Determine how many gas-fired power stations are needed to meet the demand of the UK.

   

   

number of gas-fired power stations needed = ....................................

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4b4 marks

The UK has only 32 active gas-fired power stations. 

Calculate the shortfall in power.

 
 
power shortfall = .................................... W

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4c1 mark
Suggest an energy resource that could make up the shortfall without producing further carbon emissions.

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4d4 marks
Discuss the advantages and disadvantages of gas-fired power stations.

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5a3 marks
Figure 1 shows a cross-section of a Tube station on the London Underground.

5-2-h-2a-tube-station

Figure 1

A group of students are learning about the station in a physics lesson before they visit it on a school trip.

When the students exit the station, they will ascend to street level in an elevator.

Student A says that the passengers in the lift will gain gravitational potential energy as they travel in the lift.

Student B says that they will not gain gravitational potential energy, because they are below ground level.

State which student is correct and explain your answer.

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5b5 marks

The Tube station was designed to maximise efficiency.

The station has an upward-sloping track at its entrance and a downward-sloping track at its exit.

The driver uses breaks to stop the train and uses a motor to make the train move away.

Explain how the design of the station increases the efficiency of the trains. Use ideas about wasted energy in your answer.

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5c3 marks
Prior to 1968, trains in the UK were powered by coal. Now the UK is beginning to move toward a railway system powered by electricity.

Explain why coal is no longer used to power trains.

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5d2 marks
Using electricity to power trains is better for the environment than using coal, however, there are still disadvantages.

State one environmental advantage and one disadvantage of using electricity to power trains.

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