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Consider a spherical shell of radius R at temperature T. The black body radiation inside it can be considered as an ideal gas of photons with internal energy per unit volume `u=U/V propT^4` and pressure `P=1/3(U/V)`. If the shell now undergoes an adiabatic expansion the relation between T and R is :A. `T prop e^(-R)`B. `T prop e^(-3R)`C. `T prop (1)/(R )`D. `T prop (1)/(R^(3))` |
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Answer» Correct Answer - C `p = (1)/(3)(U)/(V)` `(nRT)/(V) prop (1)/(3)T^(4)` `VT^(3) = const` `(4)/(3)piR^(3)T^(3) = const` `T R = const` `T prop (1)/(R )` |
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