Physics · May / June 2017 · Paper 12 · Question 25

A metal box has four different surfaces; dull black, shiny black, dull silver and shiny silver. The box is filled with boiling water so that each surface is at the same temperature. A sensor measures the amount of radiation from each surface. [diagram of a metal box with labelled surfaces 'shiny silver' and 'dull silver', a sensor and a meter] Which surface emits the least radiation and which surface emits the most radiation?

1. Aleast: dull black, most: shiny silver
2. Bleast: dull silver, most: shiny black
3. Cleast: shiny black, most: dull silver
4. Dleast: shiny silver, most: dull black

As printed in the paper