Exam practice
Exam questions
Write your answer. Then open the mark scheme and tick each point you made.
- Question 1 of 103 marks
Name the energy store that fills when: (a) an object speeds up, (b) an object is lifted higher, (c) a spring is stretched.
Mark scheme
- (a) Kinetic store
- (b) Gravitational potential store
- (c) Elastic store (accept: elastic potential, strain)
- Question 2 of 102 marks
A ball is dropped from a window. Describe the energy transfer as it falls.
Mark scheme
- Its gravitational potential store empties (accept: decreases)
- Its kinetic store fills (accept: increases)
- Question 3 of 101 mark
State the law of conservation of energy.
Mark scheme
- Energy cannot be created or destroyed (accept: the total energy stays the same; energy is only transferred between stores)
- Question 4 of 102 marks
A motor is supplied with 500 J of energy. It transfers 350 J usefully. Calculate the energy that is wasted, and state what happens to this energy.
Mark scheme
- 500 − 350 = 150 J
- It is dissipated (accept: it heats the motor and the surroundings; it goes to the thermal store of the surroundings)
- Question 5 of 102 marks
A label shows that 100 g of a breakfast cereal provides 1600 kJ. Calculate the energy in a 50 g bowl of the cereal. Give your answer in kJ and in J.
Mark scheme
- 800 kJ
- 800 000 J
- Question 6 of 102 marks
A 2 kW heater is used for 3 hours. Electricity costs 30p per kWh. Calculate the cost.
Mark scheme
- Energy = 2 × 3 = 6 kWh
- Cost = 6 × 30 = 180p (accept: £1.80)
- Question 7 of 102 marks
Give one advantage and one disadvantage of using wind turbines to generate electricity.
Mark scheme
- Advantage: wind is renewable (accept: it will not run out; no carbon dioxide is released as the turbines run; there is no fuel to pay for)
- Disadvantage: no electricity is generated when there is no wind (accept: the output depends on the weather; some people think turbines spoil the view)
- Question 8 of 103 marks
A can of drink at 5 °C is left in a room at 20 °C. Describe and explain what happens to the temperature of the can.
Mark scheme
- The temperature of the can rises
- Energy is transferred from the warmer room to the colder can
- It stops rising at 20 °C, when the can and the room are at the same temperature (accept: thermal equilibrium)
- Question 9 of 102 marks
Explain, using ideas about particles, how energy is conducted along a metal spoon.
Mark scheme
- The particles at the hot end vibrate more
- They pass energy on to the particles next to them (accept: they knock into their neighbours)
- Question 10 of 102 marks
Explain why a woolly hat keeps your head warm.
Mark scheme
- Wool traps air
- Air is a poor conductor (accept: air is an insulator), so energy is transferred from your head more slowly