State the first law of thermodynamics and write its limitations.
(N/A) The first law of thermodynamics is a statement of the law of conservation of energy. It states that if a quantity of heat $dQ$ is supplied to a system,it is used to increase the internal energy $dU$ of the system and to do work $dW$ by the system against the surroundings. Mathematically,it is expressed as: $dQ = dU + dW$.
Limitations of the first law of thermodynamics:
$1$. It does not indicate the direction of the process. For example,it does not explain why heat cannot spontaneously flow from a cold body to a hot body.
$2$. It does not specify the conditions under which the conversion of heat into work is possible.
$3$. It does not tell us about the extent of conversion of heat into work,i.e.,it does not explain why heat cannot be completely converted into work in a cyclic process.
Limitations of the first law of thermodynamics:
$1$. It does not indicate the direction of the process. For example,it does not explain why heat cannot spontaneously flow from a cold body to a hot body.
$2$. It does not specify the conditions under which the conversion of heat into work is possible.
$3$. It does not tell us about the extent of conversion of heat into work,i.e.,it does not explain why heat cannot be completely converted into work in a cyclic process.
Explore More
Similar Questions
If heat given to a system is $6 \, kcal$ and work done is $6 \, kJ$,then the change in internal energy is ....... $kJ$.
Easy
View SolutionGiven that $1\,g$ of water in liquid phase has volume $1\,cm^3$ and in vapour phase $1671\,cm^3$ at atmospheric pressure and the latent heat of vaporization of water is $2256\,J/g$,the change in the internal energy in joules for $1\,g$ of water at $373\,K$ when it changes from liquid phase to vapour phase at the same temperature 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 ............ $J kg^{-1}$.
$A$ thermally insulated rigid container of $1 \,L$ volume contains a diatomic ideal gas at room temperature. $A$ small paddle installed inside the container is rotated from the outside,such that the pressure rises by $10^{5} \,Pa$. The change in internal energy is close to ............... $J$.
MediumKVPY 2018
View SolutionDuring a thermodynamic process,the pressure of a fixed mass of gas is changed in such a way that the gas releases $20 \ J$ of heat and $10 \ J$ of work is done on the gas. If the initial internal energy of the gas is $40 \ J$,then the final internal energy is ...... $J$.
Medium
View SolutionVedclass Products
For Students
Vedclass Test Series
Mock tests in real JEE/NEET style with performance analysis. 5-day free trial.
Start Free TrialFor Teachers
Exam Paper Generator
Generate Set A/B/C/D exam papers from 7.5L+ questions in 2 minutes. 3 chapters free.
Try FreeFor Institutes
Online Exam Module
Live online exams with unlimited students, 360° analytics & white-label branding.
See Demo