(a) Define emissivity of a surface. (b) State the physical law that relates the total…
PHYSICS · Subjective · CBSE · Physics · Thermal Properties of Matter · Thermal Properties of Matter
Problem
(a) Define emissivity of a surface.
(b) State the physical law that relates the total radiant power per unit area of a surface to its absolute temperature and its emissivity.
(c) A dull black kettle and a shiny polished kettle are both filled with water at the same temperature and kept on identical benches in a room. Using the idea of emissivity, explain qualitatively why the dull black kettle cools faster than the polished one.