In supplying $400$ calories of heat to a system,the work done will be

$A$ system is given $300$ calories of heat and it does $600$ joules of work. How much does the internal energy of the system change in this process? $(J = 4.18 \text{ Joules/cal})$ (in joule)

$Assertion:$ The heat supplied to a system is always equal to the increase in its internal energy.
$Reason:$ When a system changes from one thermal equilibrium to another,some heat is absorbed by it.

The first law of thermodynamics is concerned with the conservation of

In a thermodynamic process,the pressure of a fixed mass of a gas is changed in such a manner that the gas molecules release $20 \ J$ of heat and $10 \ J$ of work is done on the gas. If the initial internal energy of the gas was $40 \ J$,then the final internal energy will be ........ $J$.

Heat given to a system is $35 \ J$ and work done by the system is $15 \ J$. The change in the internal energy of the system will be ..... $J$.