Energy resources — final check

1. describe

(a) Describe how a coal-fired power station generates electricity. In your answer, name the boiler, the turbine and the generator. (b) Describe the difference between solar cells and solar panels. (c) Describe how a hydroelectric dam generates electricity.

(a) Coal-fired power station

(b) Solar cells and solar panels

(c) Hydroelectric dam

2. identify / state / explain

(a) A country generates electricity from coal, wind, waves and nuclear fuel. Identify the one of these four whose energy does not come from the Sun’s radiation. (b) State one way in which the process that releases energy in the Sun is different from what happens in a nuclear power station today. (c) A pupil says that fusion power stations already supply much of the world’s electricity. Explain why this is incorrect.

(a) Not from the Sun’s radiation

(b) The Sun and a nuclear power station

(c) Why the pupil is wrong

3. state / give / describe

(a) State what is meant by a renewable energy resource. (b) Give two renewable and two non-renewable energy resources. (c) Describe one advantage and one disadvantage of wind turbines, in terms of renewability, reliability or environmental impact. (d) Describe one advantage and one disadvantage of a nuclear power station, in terms of scale, renewability or environmental impact.

(a) Renewable

(b) Examples

(c) Wind turbines

(d) Nuclear power station

4. state / explain / suggest

Two electric kettles each boil 1 litre of water, starting from the same temperature. Kettle X stays cool and quiet. Kettle Y gets a hot case and makes a loud noise while it boils. (a) State what is meant by the efficiency of an energy transfer. (b) State which kettle is more efficient, and explain your answer. (c) Suggest one change to kettle Y that would make it more efficient, and explain why it works.

(a) Efficiency

(b) The more efficient kettle

(c) A change to kettle Y

5. calculate

(a) A water pump’s motor takes in 1.6 kW of electrical power and gives a useful power output of 1200 W to the water. Calculate its efficiency. (b) A hospital’s diesel generator is 30 % efficient. It gives an electrical power output of 72 kW. Calculate the total power input from the burning diesel. (c) For every 50 kJ of electrical energy put into a crane’s motor, the motor passes 40 kJ to its gearbox, and the gearbox passes 34 kJ to the cable that lifts the load. Calculate the total energy wasted.

(a) Efficiency of the motor: ______________ unit ________

(b) Total power input: ______________ unit ________

(c) Total energy wasted: ______________ unit ________