A student measures emission from the four differently finished faces of a hot metal cube. The student always measures the matt black face first and the shiny face last. The water inside the cube cools during the experiment. Which improvement best removes this source of bias?
Repeat each face at the same measured water temperature.
Repeat each face at a different measured detector distance.
Take more readings in the same order as the water cools.
Take more readings after removing water from the cube.
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.