If heat given to a system is $6 \, kcal$ and work done is $6 \, kJ$,then the change in internal energy is ....... $kJ$.

$1 \, kg$ of a gas does $20 \, kJ$ of work and receives $16 \, kJ$ of heat when it is expanded between two states. $A$ second kind of expansion can be found between the initial and final states which requires a heat input of $9 \, kJ$. The work done by the gas in the second expansion is ....... $kJ$.

Is it possible to convert internal energy into work or mechanical energy?

First law of thermodynamics is represented by

Write the sign convention for internal energy in thermodynamics.

An electric appliance supplies $6000 \, J/min$ of heat to the system. If the system delivers a power of $90 \, W$,how long (in $sec$) would it take to increase the internal energy by $2.5 \times 10^{3} \, J$?