A) black lamp
B) cavity maintained at constant temperature
C) platinum black
D) a lamp of charcoal heated to high temperature
Correct Answer: B
Solution :
Materials like black velvet or lamp black come close to ideal black bodies, but the best practical realization of an ideal black body is a small hole leading into a cavity maintained at constant temperature as this absorbs 98% of the radiation incident on them. Cavity approximating an ideal black body is shown in the figure. Radiation entering the cavity has little chance of leaving before it is completely absorbed.You need to login to perform this action.
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