If a system changes from a state P1V1 to P2V2 by two paths then the quantity which remains unchanged is _.
Correct answer: C. dQ-dW
- A. dQ
- B. dW
- C. dQ-dW
- D. dQ+dW
Explanation
The quantity that remains unchanged is known as a state function, which depends only on the initial and final states of the system and is independent of the path taken between those states. The only state function among the given options is dQ - dW.dQ is the heat added to the system, and dW is the work done on the system. The first law of thermodynamics states that the change in internal energy of a system is equal to the heat added to the system minus the work done on the system, i.e., ΔU = dQ - dW. Thus, the quantity dQ - dW is equal to the change in internal energy, which is a state function.
Report an error
The more specific you are, the faster it gets fixed. A source beats an opinion.
Prefer email? [email protected]
About First Law of Thermodynamics
The first law relates heat supplied, work done and the change in internal energy through energy conservation. Problems use sign conventions and apply the law to isothermal, adiabatic, isobaric and isochoric processes. Internal energy is a state function, while heat and work depend on the path followed.
Practise Thermodynamics
714 free Thermodynamics MCQs from Physics, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Discussion
Stuck on an option, or know a faster way to get there? Ask or explain it here.
No comments yet. Be the first to explain this one.
Exams that ask Physics questions like this
Physics is on 16 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.
More First Law of Thermodynamics questions
A thermodynamic system undergoes a process in which its internal energy decreases by 300 J. If at the same time, 120 J of work is done on the system, find the heat lost by the system.
Which one of the following is the correct demonstration of the first law of thermodynamics?
If the reaction is carried out at constant volume and no work is done, then the change in internal energy is equal to which factor?
Internal energy is _of path.
A monatomic ideal gas is thermally insulated, so no heat can flow between it and its surroundings. Is it possible for the temperature of the gas to rise?
Which of the following is the statement of the first law of thermodynamics?