What is the net amount of heat entering the system in a cyclic process equivalent to?

$A$ diatomic gas has an initial internal energy of $80 cal$. $A$ work of $18 cal$ is done on the gas and the gas releases heat energy of $42 J$. The final internal energy of the gas is

Which of the following laws of thermodynamics defines the term internal energy?

The $P-V$ diagram of a system undergoing a thermodynamic transformation is shown in the figure. The work done by the system in going from $A \to B \to C$ is $30 \ J$ and $40 \ J$ of heat is given to the system. The change in internal energy between $A$ and $C$ is ....... $J$.

$A$ 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

$A$ unit mass of a liquid with volume $V_1$ is completely changed into a gas of volume $V_2$ at a constant external pressure $P$ and temperature $T$. If the latent heat of evaporation for the given mass is $L$,then the increase in the internal energy of the system is: