Thermal Physics - Blackbody Radiation

If the absolute temperature of a blackbody is increased by a factor of 3, the energy radiated per second per unit area does which of the following

A. Decreases by a factor of 81
B. Decreases by a factor of 9
C. Increases by a factor of 9
D. Increases by a factor of 27
E. Increases by a factor of 81
(GR0177 #35)
Solution:

Blackbody radiation: u = σT4

Thus, if T increases then u (energy) increases
(A) and (B) are FALSE.

The ratio of energy radiated is



Answer: E

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