AQA GCSE Physics (8463), Higher tier · Energy › Energy stores and changes
Practise Energy stores and systems. 12 exam-style questions on this subtopic, at up to four difficulty levels, with full mark schemes and a progress tracker. Free, no account needed.
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The student heats some water in an electric kettle. Name the energy store of the water that increases.
Thermal (internal) energy store
Name the energy store of a stretched elastic band.
Elastic potential
Name the energy store of the uranium fuel used in a nuclear power station.
Nuclear
State the energy store that decreases in a torch's battery as it powers a lamp.
Chemical
Sample questions
Written for this site in the style of AQA exam questions. They are not taken from real past papers.
Question 1Easy4 marks
Energy can be stored in different ways.
(a) A student stretches a rubber band. Which energy store of the rubber band increases? Tick (✓) one box.[1]
Chemical
Elastic potential
Gravitational potential
Kinetic
(b) The student heats some water in an electric kettle. Name the energy store of the water that increases.[1]
(c) Energy is transferred to the kettle electrically, by a current. Give two other ways that energy can be transferred from one store to another.[2]
Show the answer and mark scheme
(a)Answer: Elastic potential
(b)Answer: Thermal (internal) energy store
thermal / internal (energy store)
(c)Answer: Any two of: by heating; mechanically (by a force doing work); by radiation (e.g. light or sound waves)
by heating
mechanically / by (a) force(s) doing work
by radiation / (light or sound) waves
Question 2Medium7 marks
A student throws a tennis ball vertically upwards. The ball rises, stops for an instant at its highest point and then falls back down.
(a) Describe the changes in the way energy is stored as the ball moves from the student's hand to its highest point.[2]
(b) Explain why the ball has no kinetic energy at its highest point.[1]
(c) Air resistance acts on the ball as it moves. Explain how air resistance affects the maximum height the ball reaches.[2]
(d) The student catches the ball at the same height it was thrown from. Compare the kinetic energy of the ball just before it is caught with its kinetic energy just after it was thrown. Give a reason for your answer.[2]
Show the answer and mark scheme
(a)Answer: The kinetic energy store of the ball decreases and its gravitational potential energy store increases.
kinetic energy (store of the ball) decreases
gravitational potential energy (store of the ball) increases
(b)Answer: Its speed is zero at the highest point.
the speed / velocity of the ball is zero (at the highest point)
(c)Answer: Work is done against air resistance, so some energy is dissipated to the thermal store of the surroundings and less is transferred to the gravitational potential store — the ball does not rise as high.
(work is done against air resistance so) some energy is dissipated / transferred to the thermal store of the surroundings / air
so less energy is transferred to the gravitational potential energy store (so the maximum height is lower)
(d)Answer: The kinetic energy is less when it is caught, because energy has been dissipated by air resistance on the way up and on the way down.
kinetic energy is less (when it is caught)
(because) energy has been dissipated (to the surroundings) due to air resistance / work done against air resistance
Question 3Hard8 marks
An electric kettle has a power of 2.2 kW. The kettle contains 0.80 kg of water at 10 °C. The kettle is switched on for 150 s, and in this time the water is heated to 100 °C. Specific heat capacity of water = 4200 J/kg °C
(a) Describe the changes in the way energy is stored while the kettle heats the water.[2]
(b) Calculate the increase in the thermal energy store of the water. Use the Physics Equations Sheet.[2]
(c) Calculate the energy transferred to the kettle in 150 s.[2]
(d) Calculate the percentage of the energy transferred to the kettle that ends up in the thermal energy store of the water.[2]
Show the answer and mark scheme
(a)Answer: Energy transferred electrically increases the thermal store of the element, which heats the water so the thermal store of the water increases; some energy is dissipated to the thermal store of the kettle and surroundings.
energy is transferred electrically to (the thermal store of) the heating element
the thermal energy store of the water increases
some energy is dissipated to the thermal store of the kettle / surroundings