Explore topic-wise MCQs in Thermodynamics.

This section includes 12 Mcqs, each offering curated multiple-choice questions to sharpen your Thermodynamics knowledge and support exam preparation. Choose a topic below to get started.

1.

Oxygen gas in a piston cylinder at 300 K, 100 kPa with volume 0.1m^3 is compressed in a reversible adiabatic process to a final temperature of 700 K. Find the final pressure and volume.

A. 2015 kPa, 0.0116 m3
B. 3015 kPa, 0.0216 m3
C. 1015 kPa, 0.0416 m3
D. 4015 kPa, 0.0216 m3
Answer» B. 3015 kPa, 0.0216 m3
Discussion
2.

Argon in a light bulb is at 90 kPa and heated from 20 C to 60 C with electrical power. Find the total entropy generation per unit mass of argon.

A. 0.01 kJ/kg K
B. 0.02 kJ/kg K
C. 0.03 kJ/kg K
D. 0.04 kJ/kg K
Answer» E.
Discussion
3.

A pan contains 5 L of engine oil at 20 C, 100 kPa. Now 2 L of hot 100 C oil is mixed into the pan. Find the entropy generation.

A. 0.0728 kJ/K
B. 0.0828 kJ/K
C. 0.0928 kJ/K
D. 0.1028 kJ/K
Answer» B. 0.0828 kJ/K
Discussion
4.

A 4 L jug of milk at 25 C is placed in refrigerator where it is cooled down to a temperature of 5 C. Assuming the milk has the property of liquid water, find the entropy generated in the cooling process.

A. 0.0215 kJ/K
B. 0.0315 kJ/K
C. 0.0415 kJ/K
D. 0.0515 kJ/K
Answer» D. 0.0515 kJ/K
Discussion
5.

1kg of ammonia is contained in a piston/cylinder, as saturated liquid at 20 C. Heat is added at 100 C until a final condition of 70 C, 800 kPa is reached. Assuming the process is reversible, find the entropy generation.

A. 1.007 kJ/K
B. 1.107 kJ/K
C. 1.207 kJ/K
D. 1.307 kJ/K
Answer» E.
Discussion
6.

A piston/cylinder contains 1 kg water at 20 C, 150 kPa. The pressure is linear in volume. Heat is added from 600 C source until the water is at 1 MPa, 500 C. Find the total change in entropy.

A. 1.751 kJ/K
B. 2.751 kJ/K
C. 3.751 kJ/K
D. 4.751 kJ/K
Answer» D. 4.751 kJ/K
Discussion
7.

A piston cylinder has 2.5 kg ammonia at -20 C, 50 kPa. It is heated to 50 C at constant pressure from external hot gas at 200 C. Find the total entropy generation.

A. 0.511 kJ/K
B. 0.611 kJ/K
C. 0.711 kJ/K
D. 0.811 kJ/K
Answer» B. 0.611 kJ/K
Discussion
8.

A hot metal piece is cooled rapidly to 25 C, removing 1000 kJ from the metal. Calculate the change of entropy if energy is absorbed by vaporizing liquid nitrogen at 101.3 kPa pressure.

A. 9.929 kJ/K
B. 10.929 kJ/K
C. 11.929 kJ/K
D. 12.929 kJ/K
Answer» E.
Discussion
9.

A hot metal piece is cooled rapidly to 25 C, removing 1000 kJ from the metal. Calculate the change of entropy if energy is absorbed by ice.

A. 2.662 kJ/K
B. 3.662 kJ/K
C. 4.662 kJ/K
D. 5.662 kJ/K
Answer» C. 4.662 kJ/K
Discussion
10.

A hot metal piece is cooled rapidly to 25 C, removing 1000 kJ from the metal. Calculate the change of entropy if saturated liquid R-22 at 20 C absorbs the energy so that it becomes saturated vapor.

A. 1.950 kJ/K
B. 2.950 kJ/K
C. 3.950 kJ/K
D. 4.950 kJ/K
Answer» D. 4.950 kJ/K
Discussion
11.

An insulated cylinder/piston contains R-134a at 1 MPa, 50 C, volume of 100 L. The R-134a expands, dropping the pressure in the cylinder to 100 kPa. The R-134a does 190 kJ of work against the piston during this process. Is that possible?

A. yes
B. no
C. cannot be determined
D. none of the mentioned
Answer» B. no
Discussion
12.

1 kg of air at 300 K is mixed with 1 kg air at 400 K in a constant pressure process at 100 kPa and Q = 0. Find the entropy generation in the process.

A. 0.0207 kJ/K
B. 0.0307 kJ/K
C. 0.0407 kJ/K
D. 0.0507 kJ/K
Answer» B. 0.0307 kJ/K
Discussion