During the process $A \rightarrow B \rightarrow C$,the work done is $50 \, J$ and the heat supplied is $20 \, cal$. Find the change in internal energy between $A$ and $C$ in $J$. (in $, J$)

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 ....... $J$.

$7$ mole of a certain monoatomic ideal gas undergoes a temperature increase of $40 K$ at constant pressure. The increase in the internal energy of the gas in this process is $.... J$ (Given $R = 8.3 J K^{-1} mol^{-1}$)

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

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

Write the sign convention for internal energy in thermodynamics.