Transfer of Thermal Energy (Cambridge (CIE) IGCSE Physics)

In a very common classroom Physics demonstration, a teacher sets up a rod, as shown in the diagram. Half of the rod is copper, the other half is wood.

She sticks four lead balls to the rod using wax. The wax melts when its temperature rises a small amount, causing the ball to fall off.

The teacher heats the rod in the centre, with something more gentle than a Bunsen burner, that will not burn the wood.

Which ball falls off first?

Which of the following statements about energy transfer is correct?

A lit match is placed above a thermometer.

Which row in the table shows how the thermal energy from the lit match reaches the thermometer?

The walls of a vacuum flask contain two layers of glass, separated by a vacuum.

Which method(s) of thermal energy transfer are prevented by the vacuum?

In modern housing, it is convenient to locate heaters so they are not on the walls, taking up valuable wall space for furniture.

Other than wall-mounted radiators, two other options would be viable: ceiling heaters or underfloor heaters.

Which of the two options would heat the room more effectively and why?

Extended Tier Only

Which of the following processes take place in a non-metal to allow the conduction of thermal energy?

Two cars sit side by side, a black car and a white car. It is Summer.

During the day both cars absorb infrared radiation from the Sun, and during the night, both cars lose energy by emitting infrared radiation.

Which car heats up more quickly during the day, and which car cools down more quickly at night?

An astronaut aboard the International Space Station (ISS) lights a match.

Using ideas about convection, what does the flame look like?

Of the following modes of thermal energy transfer, which one transfers energy at the greatest speed?

A student suggests some uses for the knowledge that black and white objects emit and absorb different amounts of infrared radiation.

Which of her suggestions is correct? 

A family goes on a picnic and they want their food to stay cold. 

In order to achieve this, they put two ice packs with the picnic food in a hamper.

Where should both ice packs be placed in order to keep the food as cool as possible?