For an adiabatic compression W=100J, what will be ∆U?
Correct answer: C. +100 J
- A. -100 J
- B. 0 J
- C. +100 J
- D. None
Explanation
In an adiabatic process, there is no heat exchange with the surroundings (Q = 0). According to the First Law of Thermodynamics, the change in internal energy (∆U) is given by ∆U = Q - W. Since Q = 0, the equation simplifies to ∆U = -W. During adiabatic compression, work is done on the system, and W = -100 J (since work done on the system is positive), leading to ∆U = +100 J. Therefore, the correct answer is Option C. Other options are incorrect because they do not account for the increase in internal energy due to the positive work done on the system.
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 system absorbs 10 kJ of heat at a constant volume and its temperature rises from 270 °C to 370 °C. The value of ∆U is:
During the adiabatic expansion of 2 moles of a gas, the internal energy of the gas is found to decrease by 2 joules. The work done during the process on the gas will be equal to:
A fixed mass of an ideal gas undergoes the changes represented by X --> Y --> Z --> X as shown below.
For an adiabatic expansion:
Compressed air coming out of punctured football becomes cooler because of:
Sound passes through the air under the following process: