Efficiency & Energy Resources (Edexcel GCSE Physics)

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

Figure 13

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

i) State two other renewable sources of energy.

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

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

[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.

efficiency = ............................................................[2]

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

[1]

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.

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.  

Figure 2

i) Calculate the amount of wasted energy. 

wasted energy = ..................... J[1]

ii) Calculate the efficiency of the steam engine.

Use the equation 

efficiency = ............................[2]

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]

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

State two non‐renewable energy sources.

Figure 9 shows the renewable energy sources used in the UK in 2015. Figure 9 is to scale.

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]

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

Figure 10

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

Figure 11 shows a wind turbine.

Figure 11

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

The electrical power demand of the UK at any given time is at least .

An average gas-fired power station has a power output of .

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

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

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

Calculate the shortfall in power.

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

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

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

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

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.

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.

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.

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.