$A$ gas is taken from state $A$ to state $B$ along two different paths $1$ and $2$. The heat absorbed and work done by the system along these two paths are $Q_1, Q_2$ and $W_1, W_2$ respectively. Then:

The first law of thermodynamics is concerned with the conservation of

The latent heat of vaporization of water is $2240 \, J/g$. If the work done in the process of vaporization of $1 \, g$ is $168 \, J$,then the increase in internal energy is .... $J$.

$1 \ cc$ of water at its boiling point $(100^{\circ} \ C)$ is converted into steam by supplying $540 \ \text{calories}$ of heat. The volume of steam is $1671 \ cc$. If atmospheric pressure is $1.013 \times 10^5 \ \text{Nm}^{-2}$ and $J = 4.18 \ \text{joule/cal}$, the approximate value of heat required to overcome the molecular attraction is ........ $\text{cal}$.

$A$ gas is compressed at a constant pressure of $50 \,N/m^2$ from a volume of $10 \,m^3$ to a volume of $4 \,m^3$. Energy of $100 \,J$ is then added to the gas by heating. Its internal energy is

$110\; J$ of heat is added to a gaseous system,whose internal energy change is $40\; J$,then the amount of external work done is ........ $J$.