(i) State Wien’s displacement law for blackbody radiation, clearly identifying each…
PHYSICS · Subjective · CBSE · Physics · Thermal Properties of Matter · Thermal Properties of Matter
Problem
(i) State Wien’s displacement law for blackbody radiation, clearly identifying each physical quantity involved.
(ii) Using this law, explain qualitatively how the predominant colour of radiation emitted by a blackbody changes as its temperature is raised from about 1000K to 6000K. Quote the approximate visible wavelength bands for red, yellow and blue light in your discussion.
(iii) An electric room-heater element is seen to glow dull red soon after it is switched on, but after a few minutes appears almost white. Give a reasoned explanation for this observation on the basis of part (ii).