A glass component passes through three infrared-heating stages. During these stages, it exchanges energy with its surroundings only by radiation.
| Stage | Duration / s | Average absorbed power / W | Energy absorbed / kJ | Average emitted power / W | Energy emitted / kJ |
|---|---|---|---|---|---|
| 1 | 20 | 500 | - | - | 8.0 |
| 2 | 30 | 400 | - | 320 | - |
| 3 | 40 | - | 18 | ? | - |
The component has no overall change in internal energy between the start of stage 1 and the end of stage 3.
Calculate the average emitted power during stage 3.
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.