An electric heater supplies heat to a system at a rate of $100 \text{ W}$. If the system performs work at a rate of $75 \text{ J/s}$,then the rate at which internal energy increases will be: (in $\text{ W}$)

The $P-V$ diagram of a system undergoing a thermodynamic transformation is shown in the figure. The work done on the system in going from $A \to B \to C$ is $50 \, J$ and $20 \, cal$ of heat is given to the system. The change in internal energy between $A$ and $C$ is ...... $J$.

If $\Delta Q$ and $\Delta W$ represent the heat supplied to the system and the work done on the system respectively,then the first law of thermodynamics can be written as,where $\Delta U$ is the change in internal energy.

When $1500 \ J$ of heat is supplied to a gas at a constant pressure of $2.5 \times 10^{5} \ N/m^{2}$,the volume increases by $2.5 \times 10^{-3} \ m^{3}$. The increase in the internal energy of the gas is ..... $J$?

If $Q$,$E$,and $W$ denote respectively the heat added,change in internal energy,and the work done by a closed cycle process,then

In how many ways can the internal energy of a system be changed?