A thermal sensor is placed in a vacuum chamber. It exchanges energy with its surroundings only by radiation. The radiation reaching the sensor remains unchanged during the test.
| Time interval | Energy absorbed by the sensor | Energy emitted by the sensor |
|---|---|---|
| first 60 s | 18 J | 42 J |
| next 60 s | 18 J | 30 J |
The temperature of the sensor falls during both time intervals, but falls more slowly during the second interval.
Calculate the average net power loss from the sensor during the first 60 s.
Explain why the temperature of the sensor falls more slowly during the second time interval and what happens to its temperature if the conditions remain unchanged for a long time.
96 exam-style questions on Edexcel GCSE Physics 5.3 Black body radiation, covering 5.3.1 Emission of radiation and temperature, 5.3.2 Radiation balance and constant temperature, and 5.3.3 The temperature of the Earth. Each one has a worked solution and a mark scheme showing where the marks go.