A student investigates how surface finish affects the emission of infrared radiation. Two identical metal panels are placed in the same room. One panel has a matt black surface and the other has a shiny silver surface. Both panels start at the same temperature. The student measures how long each panel takes to cool from 70 ∘C70\ ^{\circ}\text{C}70 ∘C to 60 ∘C60\ ^{\circ}\text{C}60 ∘C.
The matt black panel takes 180 s to cool through this temperature range. The shiny silver panel takes 300 s. State which panel is the better emitter of infrared radiation.
Explain how the measurements support your answer to part (a).
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.