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 $\text{ W}$)

If a system undergoes contraction of volume,then the work done by the system will be:

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 $2.5 \times 10^{3} \, J$?

Which of the following statements is incorrect regarding the first law of thermodynamics?

The internal energy change in a system that has absorbed $2 \, kcal$ of heat and done $500 \, J$ of work is ...... $J$.

Consider $1 \,kg$ of liquid water undergoing a change in phase to water vapour at $100^{\circ} C$. At $100^{\circ} C$,the vapour pressure is $1.01 \times 10^5 \,N m^{-2}$ and the latent heat of vaporization is $22.6 \times 10^5 \,J kg^{-1}$. The density of liquid water is $10^3 \,kg m^{-3}$ and that of vapour is $\frac{1}{1.8} \,kg m^{-3}$. The change in internal energy in this phase change is nearly ............ $J kg^{-1}$.