A thermal sensor is tested in a chamber and exchanges energy with its surroundings only by radiation. During one test, the average power absorbed and the change in the sensor's internal energy are recorded over a fixed time.
| Quantity | Value |
|---|---|
| Average power absorbed | 42 W |
| Decrease in internal energy | 4.8 kJ |
| Duration of test | 80 s |
No other energy transfers occur.
What is the average power emitted by the sensor during this test?
an average power emitted of 42 W42\,\mathrm{W}42W
an average power emitted of 18 W18\,\mathrm{W}18W
an average power emitted of 60 W60\,\mathrm{W}60W
an average power emitted of 102 W102\,\mathrm{W}102W
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.