A metal block is made from mixture of 2.4 kg of aluminium, 1.6 kg of brass and 0.8 kg of copper. The metal block is initially at $20^{\circ} \mathrm{C}$. If the heat supplied to the metal block is 44.4 cal . Find the final temperature of the block if specific heats of aluminium, brass and copper are $0.216,0.0917$ and $0.0931 \mathrm{cal} \mathrm{kg}^{-10} \mathrm{C}^{-1}$ respectively

An ideal gas is found to obey $p V^{\frac{3}{2}}=$ constant during an adiabatic process. If such a gas initially at temperature $T$ is adiabatically compressed to $\frac{1}{4}$ th of its volume, then its final temperature is

The condition $d W=d Q$ holds good in the following process.

The efficiency of a Carnot engine found to increase from $25 \%$ to $40 \%$ on increasing the temperature ( $T_1$ ) of source alone through 100 K . The temperature $\left(T_2\right)$ of the sink is given by