1. 1
   A remote island community is deciding between building a wind farm and installing a diesel generator to supply electricity. Tests on the diesel generator show that for every 500 J of chemical energy supplied by the fuel, 180 J of useful electrical energy is produced.

   (a)

   Which of these two energy resources is renewable?

   [1 mark]

   • AThe wind farm
   • BThe diesel generator
   • CBoth are renewable
   • DNeither is renewable

   (b)

   Tests on the diesel generator show that for every 500 J of chemical energy supplied by the fuel, 180 J of useful electrical energy is produced. What is the efficiency of the diesel generator?

   [1 mark]

   • A2.8%
   • B64%
   • C180%
   • D36%

   (c)

   State how efficiency is defined, and explain why the diesel generator's efficiency is always less than 100%.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   A homeowner installs solar cells on the roof to generate electricity, and a neighbour installs solar panels on their roof to heat water for their home.

   (a)

   A homeowner installs solar cells on the roof of their house. What do these solar cells directly do?

   [1 mark]

   • AStore wind energy for later use
   • BTransfer infrared radiation from the Sun into heated water
   • CTransfer light energy from the Sun directly into electrical energy
   • DBurn a fossil fuel to generate electricity

   (b)

   The neighbour's solar panels are used to heat water for their home. How do solar panels achieve this?

   [1 mark]

   • AThey transfer light energy from the Sun directly into electrical energy, which is then used to boil the water
   • BThey absorb infrared (and other electromagnetic) radiation from the Sun, transferring the energy to heat water flowing through them
   • CThey use wind passing over the panels to spin a small turbine
   • DThey store geothermal energy from underground

   (c)

   Explain the key difference between the solar cells and the solar panels described here.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   A national energy planning committee is comparing a hydroelectric dam with a nuclear power station as options for a new power plant.

   (a)

   Describe two advantages and one disadvantage of using a hydroelectric dam to generate electricity, in terms of renewability, availability, reliability, scale and environmental impact.

   [3 marks]

   (b)

   Describe, including reference to a boiler, turbine and generator, how useful electrical power is generated from nuclear fuel, and describe one advantage and one disadvantage of nuclear power compared with a hydroelectric dam.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   A national energy policy report compares current fossil fuel power stations with the possibility of future power stations based on nuclear fusion, which is currently only used to generate energy inside the Sun.

   (a)

   Describe, with reference to a boiler, turbine and generator, how a power station generates electricity by burning a fossil fuel, and discuss two advantages and two disadvantages of using fossil fuels to generate electricity, compared with a mixture of renewable energy resources, in terms of renewability, availability, reliability, scale and environmental impact.

   [6 marks]

   (b)

   Explain why radiation from the Sun is described as the main source of energy for almost all of our energy resources, except for geothermal, nuclear and tidal energy, and explain what is meant by nuclear fusion, describing why research into using nuclear fusion to generate electrical energy on Earth might offer benefits for the future compared with current fossil fuel power stations.

   [6 marks]

   Total for question 4: 12 marks

End of questions