Two identical cans with equal masses of hot water are used to compare surface finishes. The matt black can has no lid. The shiny can has a lid. The matt black can cools faster. Which change best tests whether the surface finish caused the difference?
Remove the shiny can's lid and use different water masses.
Fit identical lids and use equal water masses and starting temperatures.
Fit different lids and use equal water masses and starting temperatures.
Remove the shiny can's lid and use different starting temperatures.
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.