AQA GCSE Temperature of Bodies(Physics)

Temperature of Bodies

A body is an object. 

A body will have a constant temperature if the incident radiation that it absorbs is equal to the emitted radiation. 

In the diagram below the rate of incident radiation will equal the rate of emitted radiation, so the temperature remains constant. 

Body absorbing and emitting radiation, so it stays at a constant temperature

Temperature of body increasing

If the rate of incident radiation is greater than the rate of emitted radiation, the temperature of the body will increase as shown below.

Body is absorbing incident radiation at a greater rate than it is emitting it.

Temperature of the body decreasing

If the body emits radiation at a faster rate than the rate of absorption, then the temperature of the body will decrease.

Everyday objects changing temperature. 

You need to be able to apply the ideas to everyday examples. In the diagram below a cup of tea is decreasing its temperature because it emits radiation at a greater rate than it absorbs radiation

Hot cupt of tea decreasing in temperature because the rate of emitting radiation is greater than the rate of absorbing radiation.

Practice Question

1.During the day, the temperature of the sand on a beach increases. Explain the temperature increase in terms of incident radiation and emitted radiation

2. The temperature of a refrigerator is kept constant. Explain how this is possible in terms of incident radiation and emitted radiation

3. When liquid water is placed into a freezer it changes into ice. Explain this change in terms of incident and emitted radiation.

Accordion Content