A blackbody radiates energy at the rate of E watt per metre² at a high…
2023
A blackbody radiates energy at the rate of E watt per metre² at a high temperature T K. When the temperature is reduced to T/3 K, the radiant energy (in watt per metre²) will be
- A.
E/16
- B.
E/27
- C.
E/81
- D.
More than one of the above
- E.
None of the above
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Correct answer: C
The radiant energy emitted by a blackbody is proportional to the fourth power of its absolute temperature, according to the Stefan-Boltzmann law. When the temperature is reduced from T to T/3, the energy becomes (1/3)^4 = 1/81 times the original. Therefore, the new radiant energy is E/81.