1
1 A student designs a container to keep a hot liquid at a high temperature.
The container is shown in the diagram.
liquid
container
made of
cardboard
He finds that the liquid cools too quickly.
Suggest two improvements to the design of the container which reduce the transfer of thermal
energy from the hot liquid to its surroundings.
For each suggestion, state the thermal transfer process that it reduces.
suggestion 1 .............................................................................................................................
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thermal transfer process ..........................................................................................................
suggestion 2 .............................................................................................................................
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thermal transfer process .......................................................................................................... [4]
[Total: 4]
2 During a picnic on a warm, dry day, a metal can of lemonade is wrapped in a damp cloth.
Evaporation cools the water in the cloth.
As the water in the cloth cools, so does the lemonade.
Explain how electrons transfer thermal energy through the metal of the can.
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.................................................................................................................................................. [3]
[Total: 3]
2
3 A metal container is used to cook food. The metal container has thick walls. Hot cooking oil at a
temperature of 120 °C is poured into the container.
The outside surface of the container gets hot. Some thermal energy passes through the metal
because vibrating atoms in the metal collide with neighbouring atoms and transfer energy to them.
Explain how the rest of the thermal energy is conducted through the metal container to the outside
surface by another process.
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.................................................................................................................................................. [3]
[Total: 3]
4 Two metal spheres of different diameters are heated to 900 °C in a hot oven. The two spheres are
removed from the oven.
(a) State and explain any difference in the initial rates of emission of radiation of thermal energy
between the two spheres.
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........................................................................................................................................... [2]
(b) One hot sphere is now heated in a hotter oven.
State and explain any effect on the rate of emission of radiation of thermal energy from that
sphere when it is removed from the hotter oven.
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........................................................................................................................................... [1]
[Total: 3]
3
5 A student carries out an experiment to compare how quickly thermal energy is conducted along
rods made from different metals. Each rod is heated at one end with a Bunsen burner flame.
Each rod carries a marker held on the rod with a little wax. When the wax melts, the marker falls.
wax
rod marker
heat
tripod
bench
Suggest three possible variables that the student should keep constant in order to make a fair
comparison between the different metals.
1. ...........................................................................................................................................
2. ...........................................................................................................................................
3. ........................................................................................................................................... [3]
[Total: 3]
4
6 Describe an experiment to demonstrate the difference between good and bad emitters of infra-red
radiation. You may include a diagram to help your description. State what readings should be taken.
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.................................................................................................................................................. [3]
[Total: 3]
5
7 The diagram shows a cross-section of the inside of a vacuum flask containing a cold liquid. The
walls of the vacuum flask are made of glass.
The vacuum flask is being used to keep a liquid cool on a hot day.
Explain how the labelled features of the vacuum flask keep the liquid cool by reducing thermal
energy transfer. Include the names of the processes involved.
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.................................................................................................................................................. [5]
[Total: 5]
6
8 Explain, in terms of molecules, how sweating helps to cool your body on a hot day.
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.................................................................................................................................................. [3]
[Total: 3]
9 A person climbs out of a swimming pool and stands in the open air.
Explain why evaporation of water from the surface of the person’s body causes the person to feel
cold.
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.................................................................................................................................................. [2]
[Total: 2]
