Question

A gas is carried through the path AB, BC
and CA according to the adjoining figure.
What is the net work done in the whole
cycle ?
4P
Pressure
P3
3V1
Volume​

Answer 1

Given : A gas is carried in a cycle through the path AB, BC  and CA

To find : Net work done in the whole  cycle

Solution :

• Now, we have given in the question that the gas is carried out through the path AB, BC and CA.

• Also it is given that body has started from A, then goes to B and then to C. Then again to comes to point A.

• So

              initially gas started from: A

              finally gas came at: A

• So, net displacement of system will be 0 because the body has came to its initial point.

• So, this concludes that this is a cyclic process.

• The internal energy change in this process is equal to zero.

• By using first law of thermodynamics, we get:

               ΔU = Q - W ...............................(I)

• Here:

              ∆U = Change in internal energy.

              Q= Heat given to system.

              W = Work done by the system.

• Now, we know that change in internal energy of the system is equal to the difference between the heat given to system and work done by the system.

• So, we can say that ∆U =0

           so by equation 1.

           Work done  = Heat given to the system.

           Hence W = Q

Answer:

              The net work done in the whole  cycle is Q.