A model Earth is initially in radiation balance. Two changes occur together: more sunlight is reflected into space, and greenhouse gases reduce outgoing infrared power. Which information is needed to determine the initial direction of temperature change?
Only the change in reflected solar power, because outgoing radiation is irrelevant.
The sizes of both power changes, because they have opposing effects.
Only the change in outgoing infrared power, because reflected sunlight is absorbed.
The sizes of both power changes, because they always cause warming.
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.