Out of the following, which statement is NOT true about black body radiation ?

$15$ g of ice at $0^\circ\text{C}$ is added to a vessel containing water at $40^\circ\text{C}$. The mass of water and water equivalent of the vessel is $60$ g. Assuming that negligible heat is taken from the surroundings, the final temperature of the mixture will be
[ $L_{\text{ice}} = 80\,\text{cal/g}$ , $S_{\text{water}} = 1\,\text{cal/g}$ ]

An ideal gas having pressure P, volume V and temperature T undergoes a thermodynamic process in which $dW = 0$ and $dQ < 0$. Then, for the gas

An ideal gas at pressure 'P' and temperature 'T' is enclosed in a vessel of volume 'V'. Some gas leaks through a hole from the vessel and the pressure of the enclosed gas falls to $P^1$. Assuming that the temperature of the gas remains constant during the leakage, the number of moles of the gas that have leaked is