A) A good absorber is a bad emitter
B) Everybody absorbs and emits radiations at every temperature
C) The energy of radiations emitted from a black body is same for all wavelengths
D) The law showing the relation of temperatures with the wavelength of maximum emission from an ideal black body is Plank?s law
Correct Answer: D
Solution :
A good absorber is a good emitter hence option (a) is wrong. Every body stops absorbing and emitting radiation at 0 K hence option (b) is wrong. The energy of radiation emitted from a black body is not same for all wavelength hence option (c) is wrong. Plank?s law relates the wavelength (l) and temperature (T) according to the relation \[{{E}_{\lambda }}{{d}_{\lambda }}=\frac{8\pi \,hc}{{{\lambda }^{5}}}\frac{1}{[{{e}^{hc/kT}}-1]}{{d}_{\lambda }}\]. Hence option (d) is correct.
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