Question

What is the work done for a constant volume process?

1. 1
2. 0
3. -1
4. 0.5

Answer 1

Correct Answer - Option 2 : 0

Concept:

The first law of thermodynamics explains the change in energy as 

∆U = Q - W.

Q is the heat absorbed and W is work done.

• Isothermal Process: The process in which temperature remains constant is called the isothermal process. 
• Internal energy is the function of temperature. If T is constant then 

∆U = 0

Q = W

• Adiabatic Process: The process in which no heat is transferred into or out of the system is called the adiabatic process. 

Adiabatic Process is represented as 

Q = 0

∆U = - W

• Isochoric process: The process in which volume is constant is called the isochoric process. 
• Volume change requires work done in form of compression or expansion of gas. 

Explanation:

Considering the statements 

1. Q = W represents adiabatic process. It is wrong as it represents the isothermal process.
2. Q = 0 represents isothermal process. It is wrong as it represents the adiabatic process. 
3. W = 0 for Isochoric Process, It is true. In the Isochoric process, the volume remains constant. if the volume is constant,  we can say no work has been done on the system.  There is no expansion or compression of the gas. So, it is true.

So, only option (c)  is true.