Best thermodynamics interview questions

Normally any interviewer tries to check whether a candidate is suitable for the present job or not with respect to attitude towards the work and knowledge about the field by asking suitable interview questions. Based on the type of job or job profile, the interview asks basic questions from different subjects.

If the student has grasped the engineering syllabus or course from the point of the basic concept of view, he/she must be able to answer the following questions. Read the following interview questions. These questions might be helpful in the GATE examination too.

Interview Questions on Thermodynamics

1. When a real gas behaves like an ideal gas?

Ans: A real gas behaves like an ideal gas in low-pressure and high-temperature conditions.

2. What is the significance of entropy?

Ans: As per the second law of thermodynamics and entropy viewpoint, any heat input to the system (Heat engine) cannot be converted completely into useful work. Some energy is lost and that is called ‘unavailable work’. The number of unavailable work increases as entropy increases.

3. What is the difference between heat transfer and thermodynamics?

Ans: Heat transfer deals with energy analysis which is in transition and depends on the modes of heat transfer like conduction, convection, radiation, or a combination of any modes. Heat transfer deals with the nonequilibrium domain and conditions while thermodynamics deals with the study of the system at equilibrium and does not depend on how heat transfer is calculated.

4. At which temperature thermal radiation can become zero? 

Ans: Not possible. Because thermal radiation becomes only zero at absolute zero temperature which can never be attained by the third law of thermodynamics.

5. Why Specific heat at constant pressure is greater than Specific heat at constant volume?

As per the first law of thermodynamics for a closed system, the change in the heat is equal to the change in internal energy and work done. During the constant pressure, when we heat the substance, some heat always is utilized for useful work, and the remaining will increase the internal energy or temperature change.

While the same scenario with a constant volume condition, the work done in the constant volume case is zero, and thus, all the heat is directly utilized in the change in the temperature. Thus, the heat required to raise or change the temperature in constant pressure conditions is more than that of a constant volume case.

The compressibility factor is a measure of a gas’s nature with respect to its closeness with an ideal gas. The ideal gas has a compressibility factor of 1. PV=ZRT, where Z is the compressibility factor.

Whenever a process takes place and heat is utilized to do useful work, the system tries to achieve the equilibrium condition with the atmosphere. The state corresponding to the surrounding condition once the useful work is achieved is known as the dead state. In a dead state, there are no possibilities of any further work.

Initially, the first law (energy conservation law) and second law were discovered and later scientists discovered a more fundamental law, and that law was named the ‘zeroth law’ of thermodynamics.

Conclusion:

These interview questions are solely based on the laws of thermodynamics and entropy concepts. These can be really helpful to all those students and graduates who are going to apply for any post related to industrial positions in thermal companies or in academic positions like a professor/teacher in engineering college.