An infrared detector is pointed at the casing of an electric motor. The surroundings and the distance between the detector and the casing remain unchanged. The detector reading increases as the casing warms from 22 ∘C22\ ^\circ\text{C}22 ∘C to 48 ∘C48\ ^\circ\text{C}48 ∘C. Which statement describes the reason for the increase in the detector reading?
Warming moves the peak of the emitted radiation to a longer wavelength.
Warming causes the casing to produce radioactive radiation.
The warmer casing emits infrared radiation at a greater intensity.
The warmer casing absorbs infrared radiation at a greater intensity.
106 exam-style questions on AQA GCSE Physics 6.3 Black body radiation, covering 6.3.1 Emission and absorption of infrared radiation and 6.3.2 Perfect black bodies and radiation. Each one has a worked solution and a mark scheme showing where the marks go.