Can work be done by a system without changing its volume?

Yes, work can be done by a system without changing its volume if the process is cyclic.

Explanation


1. In cyclic process, the system returns to its initial state. Therefore, initial volume becomes equal to final volume and hence ΔV=0.


2. Also, since system returns to initial state, the internal energy of the system remains same.


3. This is because internal energy is a state variable. It depends on initial and final state only. And if initial and final state becomes equal, then change in internal energy will be zero.


4. So, for cyclic process ΔV=0 and ΔU=0.


5. According to First law of thermodynamics,


ΔQ=ΔU+ΔW


Where ΔQ=heat supplied to the system


ΔU=change in internal energy


ΔW=work done by the system


6. So, from the first law of thermodynamics ΔQ=ΔW i.e. heat supplied to the system is converted entirely into work in a cyclic process.


7. Therefore, work can be done by a system without changing its volume.


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