Four identical metal flasks are filled with equal volumes of hot water at 90∘C90^\circ\text{C}90∘C. The outer surfaces of the flasks are finished with different colours and textures.
Which flask will show the slowest temperature drop?
matt black
matt white
shiny black
shiny silver
99 exam-style questions on CIE IGCSE Physics 2.3.3a Thermal radiation. Each one has a worked solution and a mark scheme showing where the marks go.