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.
You will be redirected in
3 sec