Transfer of thermal energy

A cotton sheet is pressed using a hot electric iron. In what way does energy pass through the iron’s metal base to the sheet?

Feb/March 2016

One plastic cup is inserted inside another. A small spacer holds the two cups apart. Hot water is then poured into the inner cup, and a lid is placed over the top, as shown. Which statement is correct?

Feb/March 2016

In an experiment, a liquid is heated at a steady rate. Its temperature rises and then finally stays the same. Which statement about this experiment is correct?

Feb/March 2016

One end of a copper rod is heated. By what method is thermal energy transferred through the copper rod?

Feb/March 2016

Two plastic cups are stacked with one inside the other. A small spacer holds the cups apart. Hot water is then added to the inner cup and a lid is fitted on top, as illustrated. Which statement is correct?

Feb/March 2016

Fig. 7.1 depicts a room containing a heater. Fig. 7.2 depicts the ceiling, which is made from an insulating material, with layers labelled: aluminium foil, foam with air trapped inside, aluminium foil.

Feb/March 2016

The Sun is the source of solar energy. Tick the box beside the resources whose energy also comes from the Sun: coal, geothermal, hydroelectric, nuclear, wind.

Feb/March 2016

The diagram illustrates the space between a hot surface and a cold surface. That space may be filled with air, solid iron, a vacuum or liquid water. Which row indicates whether heat may move between the surfaces by conduction and convection?

Feb/March 2017

A piece of wire gauze traps the ice at the bottom of a tube containing water. The water at the top of the tube reaches boiling point before the ice at the bottom melts. Why does this occur?

Feb/March 2017

Which main type of radiation is emitted by a campfire?

Feb/March 2017

In what kind of substance do free electrons take part in the transfer of thermal energy?

Feb/March 2017

Four objects are made from the same material and each has the same mass. They are all at the same temperature. The objects have different surfaces and different surface areas. Which object gives out infra-red radiation at the highest rate?

Feb/March 2017

Fig. 9.1 shows a beaker of water with an electric heating element inside it. The heating element is switched on.

Feb/March 2017

Fig. 6.1 illustrates apparatus used to demonstrate some effects of energy transfer by radiation. The matt-black glass bulb, the shiny glass bulb and the spaces above the liquid in the tube each contain air. When switched on, the heater glows red. It is positioned the same distance from each bulb.

Feb/March 2017

A teacher shows a class an experiment. A boiling tube is partly filled with water, and a few ice cubes are held at the base of the tube. The teacher then heats the boiling tube in the arrangement shown until the water at the top reaches boiling point. The ice remains unmelted. What does this show?

Feb/March 2018

A hot metal plate is positioned close to a cold metal plate. Infra-red radiation transfers thermal energy between the two plates. Which colour would make the cold plate’s temperature rise most slowly?

Feb/March 2018

Liquid evaporates from a beaker. What happens to the temperature of the liquid that is left behind, and how does this temperature change influence the rate of evaporation?

Feb/March 2018

A teacher shows a class an experiment. A boiling tube contains water, and some ice cubes are held at the base of the tube. The teacher then heats the boiling tube in the position shown until the water at the top starts boiling. The ice does not melt. What does this show?

Feb/March 2018

A metal cup is lined with plastic. Hot water is poured into the cup, and a hand is used to hold it. Which statement about how thermal energy is transferred from the water to the hand is correct?

Feb/March 2018

A thermometer is used to find the temperature inside a room in a house.

Feb/March 2018

Fig. 4.1 shows a cold plastic spoon that has just been put into hot liquid in a cup.

Feb/March 2018

Four campers are heating their food over a fire. They use rods made from different materials, all of the same dimensions, to keep their food close to the fire. Which material would be the best choice to stop their hands from becoming too hot?

Feb/March 2019

A beaker containing water is heated, and thermal energy is transferred through the water by convection. What happens to the water’s density when it is heated, and in what way does the water move?

Feb/March 2019

Four campers are heating their food over a fire. They each use a rod of identical dimensions to support the food close to the flames. Which material would be the best option for stopping their hands from becoming too hot?

Feb/March 2019

Two metal cans are the same in every respect apart from their outside finish: one has a shiny silver exterior, while the other has a dull black exterior. Each contains $300\,\text{g}$ of water at $80\,^{\circ}\text{C}$, and the water is sealed inside. Both cans are placed in a vacuum, in the darkness of outer space. What happens to the temperature of the water in each can?

Feb/March 2019

Fig. 6.1 shows the inside of an electric oven in side view.

Feb/March 2019

An electrical heater stands on the floor of a house room, and it is switched on.

Feb/March 2019

Rods that all have the same shape and size are pushed through corks into a tank containing hot water. Each rod is coated with a layer of solid wax with a low melting point. After some time, part of the wax has melted. On which rod does the wax melt first?

Feb/March 2020

A boy dives into an indoor swimming pool. He notices that the water seems colder the deeper he moves below the surface. This happens because of convection. Which statement is correct?

Feb/March 2020

A student records the mass of warm water in an open container for a period of two minutes. The container is maintained at a steady temperature. The data are shown in the table. Why does the mass of the water change?

Feb/March 2020

Metals are good thermal conductors. Insulators are poor thermal conductors. Which statement about the mechanism of thermal conductivity is correct?

Feb/March 2020

A teacher presents his class with a polystyrene cup. The cup is formed from thick plastic containing many tiny pockets of air. He asks the class why the cup is so effective at keeping a hot drink warm. Three ideas are put forward. 1. It has air inside, and air is a poor thermal conductor. 2. The air is held in small bubbles, so very little convection can take place. 3. The plastic is a poor thermal conductor. Which ideas are correct?

Feb/March 2020

A boy dives into an indoor swimming pool. As he moves further below the water surface, he observes that the water seems colder. This happens because of convection. Which statement is correct?

Feb/March 2020

Fill in the blanks with words that name the main process of thermal energy transfer in each case. A man goes for a walk on a cold day. He touches a metal gate, which removes thermal energy from his hands by [BLANK]. He holds the sides of a cup containing a hot drink. His hands gain thermal energy by [BLANK]. Some farm workers have lit a fire. The man warms his hands by the side of the fire. His hands gain thermal energy by [BLANK].

Feb/March 2020

Four samples of materials with identical dimensions are tested. Which material shows the greatest rate of thermal conduction?

Feb/March 2021

Four metal mugs with lids are each filled with the same volume of hot water at the same temperature. The mugs are made from the same metal and have the same shape and size, but the outside of each mug is painted with a different mix of texture and colour. Which mug radiates thermal energy at the greatest rate?

Feb/March 2021

One end of a copper rod is heated. By what one process is thermal energy passed through the copper rod?

Feb/March 2021

Which alteration would lead to a reduction in the rate at which an object emits radiation?

Feb/March 2021

Convection can transfer thermal energy in which states of matter?

Feb/March 2023

A metal bar, which is a good thermal conductor, is heated at one end. By which main method is thermal energy transferred along the bar?

Feb/March 2023

Fig. 4.1 shows a metal pan resting on an electric hotplate. The pan holds 200 cm$^3$ of water. The diagram is labelled "water", "metal pan" and "hotplate". The pan is heated. The water temperature in the pan rises.

Feb/March 2023

Which one of the following is not an instance of convection?

Feb/March 2024

A hollow aluminium cube is packed with very hot water. Side X of the cube lies opposite side Y. Of these two sides, one is black and the other is white. A student places the back of one hand 5 cm from side X, then straight away places the back of the other hand 5 cm from side Y. The hand near side Y is felt to be warmer than the hand near side X. Which row shows which side is black and also compares the rate at which thermal radiation is emitted from each side correctly?

Feb/March 2024

The diagram illustrates a pan for cooking food. Which row correctly shows the materials used for the base of the pan and the handle of the pan?

Feb/March 2024

Solar heating panels contain pipes through which water flows, and these pipes absorb radiation from the Sun. What surface texture and colour should the pipes have so that the water temperature increases at the fastest rate?

Feb/March 2024

A candle is used to warm some water in a glass beaker. What is the main method of heat transfer through the glass and throughout the water?

Feb/March 2025

An experiment is carried out to compare how quickly thermal energy is conducted through metal and plastic spoons. An ice cube is put on one end of each spoon, while the other end is heated gently. Which row gives the correct prediction together with the correct explanation?

Feb/March 2025

A hot object gives out thermal radiation. Which row shows two alterations that both lower the rate at which radiation is emitted?

Feb/March 2025

A student heats some water in a metal container using an electric heater, as illustrated in Fig. 6.1.

Feb/March 2025

A liquid is heated in a beaker. As the liquid’s temperature rises, its density changes. This results in energy being carried through the liquid. How does the density change, and what is this energy transfer process?

May/June 2016

A rod consists of one half glass and one half copper. Four pins A, B, C and D are fixed to the rod with wax. The rod is heated at its midpoint, as illustrated. The pins drop away once the wax has melted. Which pin drops off first?

May/June 2016

Which process uses convection?

May/June 2016

A rod is composed of one half glass and one half copper. Four pins A, B, C and D are fixed to the rod using wax. The rod is heated at the centre, as shown. The pins drop off when the wax melts. Which pin drops off first?

May/June 2016

A student proposes some applications for containers made from good thermal conductors and for containers made from poor thermal conductors. In which row are both proposed applications correct?

May/June 2016

A rod has one half made from glass and the other half made from copper. Four pins A, B, C and D are held on the rod using wax. The rod is heated at its centre, as illustrated. The pins drop away once the wax melts. Which pin drops away first?

May/June 2016

Two cars that are otherwise identical, one black and one white, start at the same initial temperature. They are then left in bright sunshine, so their temperatures rise. At night, their temperatures fall. Which car has the greater rate of temperature increase, and which car has the greater rate of temperature decrease?

May/June 2016

A liquid is warmed in a beaker. As the temperature rises, the liquid’s density changes. This leads to energy being transferred through the liquid. What change occurs in the density, and what is this energy transfer process called?

May/June 2016

What processes take place in a metal that lead to thermal conduction?

May/June 2016

A wooden beam has one section painted black and another section painted white. In daylight, the beam takes in infra-red radiation from the Sun, and at night it gives off infra-red radiation to the surroundings. Which section of the beam warms up more rapidly during the day, and which section cools down more rapidly at night?

May/June 2016

A $5.0\,\text{g}$ sample of water at $25\,^{\circ}\text{C}$ is placed on a large block of ice at $0\,^{\circ}\text{C}$. The water reaches $0\,^{\circ}\text{C}$, and part of the ice turns to water. Take the energy lost by the water to be the same as the energy gained by the ice. Determine the mass of ice that melts. The specific heat capacity of water is $4.2\,\text{J}\,(\text{g}^{-1}\,^{\circ}\text{C}^{-1})$. The specific latent heat of fusion of ice is $340\,\text{J g}^{-1}$.

May/June 2016

Which row identifies the surface that is the more effective absorber and the surface that is the more effective emitter of infra-red radiation?

May/June 2016

A student puts forward some uses for containers constructed from good thermal conductors and for containers constructed from poor thermal conductors. In which row are both proposed uses correct?

May/June 2016

Fig. 3.1 illustrates a metal plate-warmer. The plate-warmer has two small candle heaters inside it. Plates of food are set on the warming-tray above.

May/June 2016

A student is examining a mixture of water and ice. The water and ice are at the same temperature. He uses a thermometer.

May/June 2016

Researchers have established that coffee is best drunk at 60 ^{\circ}C. A designer has created a new cup intended to keep coffee at 60 ^{\circ}C. Figure 8.1 shows the cup. The labelled parts are: plastic lid, inner steel walls, shiny outer steel wall, vacuum, coffee, material Z. Material Z has a melting point of 60 ^{\circ}C. At room temperature, material Z is solid. Coffee at 90 ^{\circ}C is poured into the cup, and the coffee cools quickly to 60 ^{\circ}C.

May/June 2016

A copper bar and a wooden bar are connected together. A strip of paper is wrapped closely around the point where they meet. The centre of the bar is heated very strongly for a brief period, and the paper turns brown on only one side. Which side turns brown, and what does this indicate about wood and copper?

May/June 2017

A hollow aluminium cube contains very hot water. Face $X$ of the cube is opposite face $Y$ of the cube. Of these two faces, one is black and the other is white. A student places the back of one hand $5\,\text{cm}$ from face $X$, and then straight away places the back of the other hand $5\,\text{cm}$ from face $Y$. The hand near face $Y$ feels hotter than the hand near face $X$. Which row names the black face and correctly compares the rate at which thermal radiation is emitted from each face?

May/June 2017

A copper bar and a wooden bar are fixed together. A sheet of paper is wrapped closely around the junction. The bar is then heated strongly in the middle for a brief period, and the paper turns brown on only one side. Which side turns brown, and what does this indicate about wood and copper?

May/June 2017

Which forms of thermal energy transfer need a medium?

May/June 2017

A copper bar and a wooden bar are connected together. A strip of paper is wrapped tightly around the point where they join. The middle of the bar is then heated strongly for a short period, and the paper turns brown on only one side. Which side turns brown, and what does this indicate about wood and copper?

May/June 2017

A student uses a straw to blow air through a liquid. As a result, the liquid evaporates more rapidly and so its temperature falls. Which statement explains why the liquid that is left behind cools?

May/June 2017

A copper bar and a wooden bar are attached together. A strip of paper is wrapped tightly round the point where they meet. The bar is then heated strongly in the middle for a short time, and the paper turns brown on only one side. Which side turns brown, and what does this reveal about wood and copper?

May/June 2017

The diagrams illustrate four open dishes. Every dish has water at the same temperature. The dishes have different shapes, and a draught passes over two of them. From which container does the water evaporate at the greatest rate?

May/June 2017

A lump of ice at $-20^\circ\text{C}$ is warmed until it becomes steam. The graph showing temperature plotted against thermal energy absorbed is given. The latent heat of fusion of ice is $340\ \text{kJ kg}^{-1}$. What is the mass of the ice?

May/June 2017

A copper bar and a wooden bar are connected together. A strip of paper is wrapped very tightly around the point where they join. The bar is then heated hard at the middle for a brief period, and the paper turns brown on only one side. Which side becomes brown, and what does this indicate about wood and copper?

May/June 2017

Figure 4.1 shows a house with white wooden walls and a black wooden door. The diagram identifies the wall as white and the door as black.

May/June 2017

State the rate at which the lamp transfers energy to the surroundings.

May/June 2017

Calculate how long it takes for the water temperature to reach 100 ^{\circ}C.

May/June 2017

A footballer and a referee are talking about a puddle of water that has appeared on the pitch. The footballer is wearing a white shirt, while the referee is wearing a black shirt that is identical apart from its colour. Fig. 5.1 shows the two men looking at the puddle. The weather is bright and sunny.

May/June 2017

When the weather is warm, a carton of fresh milk is wrapped in a wet cloth. Why does this help to lower the milk's temperature?

May/June 2018

On a cold day, a metal front-door knob X and a similar plastic knob Y are both at the same temperature. Why does X seem colder when touched than Y?

May/June 2018

When a liquid is warmed, it expands. In what way does this result in the formation of a convection current?

May/June 2018

Four thermometers, each with its bulb painted a different colour, are positioned at the same distance from a radiant heater. Which thermometer has the slowest increase in temperature when the heater is switched on for the first time?

May/June 2018

The diagram shows a pan that is used to cook food. Which row gives the correct materials for the pan’s base and its handle?

May/June 2018

A saucepan of water is warmed from underneath on an electric hob. Five minutes later, the water close to the top of the saucepan is getting hot. What is the main process of heat transfer within the water?

May/June 2018

On a cold day, metal front-door knob X and a similar plastic knob Y both have the same temperature. Why does X seem colder to the touch than Y?

May/June 2018

Four thermometers, whose bulbs are painted in different colours, are positioned at equal distances from a radiant heater. Which thermometer has the slowest increase in temperature when the heater is switched on for the first time?

May/June 2018

The diagram shows a pan for cooking food. Which row correctly identifies the materials used for the base and the handle of the pan?

May/June 2018

A student builds a device to absorb thermal energy from the Sun. Fig. 6.1 presents the device. The labels shown are thermometer, Tank A, cold water, white plastic pipe, Sun, Tank B and warm water. The student puts the white plastic pipe in sunlight. The cold water moves slowly from Tank A to Tank B. Energy from the Sun warms the water in the pipe. Fig. 6.2 shows the temperatures in Tank A and Tank B. Thermometer showing temperature in Tank A and Thermometer showing temperature in Tank B, each marked from -10 ^{\circ}C to 110 ^{\circ}C.

May/June 2018

In Fig. 4.1, a Bunsen burner is used to heat a beaker of water.

May/June 2018

A student compares how much thermal energy is lost from two metal cans, X and Y. The cans are the same except for the colour of their outer surfaces. The student adds the same volume of hot water to each can and seals each one. The water temperature in each can is then measured at regular time intervals for 35 minutes.

May/June 2018

A student intends to investigate good and bad absorbers of thermal radiation. She has the apparatus in Fig. 5.1, along with cold water and a metre rule.

May/June 2018

A beaker holds some water at room temperature. A student inserts a mercury-in-glass thermometer into the water so that the bulb sits just below the water surface. Fig. 4.1 shows the setup.

May/June 2018

In which situation does thermal conduction not take place?

May/June 2019

The kettle's metal surface is hot. What happens to the cool air around the kettle when it comes into contact with the hot kettle?

May/June 2019

The outer metal surface of a kettle is hot. What occurs to the cooler air around the kettle when it touches the hot kettle?

May/June 2019

Vacuum flasks often have silver-coated walls to help keep the contents inside hot. Why are the walls silvered?

May/June 2019

On a very warm summer day, the water level in a pond drops. Which statement explains this?

May/June 2019

A person is holding an empty beaker made of glass and pouring hot water into it. Why does it take a few seconds before his hand begins to feel hot?

May/June 2019

The metal surface of a kettle is hot. What occurs to the cool air outside the kettle as it touches the hot kettle?

May/June 2019