Mechanical Engineering - Thermodynamics - Discussion


The increase in entropy of a system represents

[A]. increase in availability of energy
[B]. increase in temperature
[C]. decrease in pressure
[D]. degradation of energy

Answer: Option D


No answer description available for this question.

Pramod said: (Jun 23, 2015)  
How it is?

Sainath Rajoli said: (Jul 29, 2015)  
Entropy is the property which increase with addition of heat and decrease with removal of heat. So I think option B is the right.

Yogesh Thenuan said: (Jan 2, 2016)  
Explanation : As entropy means degree of randomness, so increase in entropy means that there is an increase in randomness. So, useful energy is degraded or lost.

Sahil said: (Aug 3, 2016)  
Answer is b because entropy is a function of temperature.

Abdul Rahman said: (Sep 12, 2016)  
I too think it is option B.

Ram said: (Sep 23, 2016)  
It is dS = dQ/T. So A is the correct answer.

S Bera said: (Jun 28, 2017)  
Please anyone explain.

Sunny said: (Jul 15, 2017)  
Hers, dS= dQ/T.

Question is what does entropy represents (Not proportional or depends). Like the differential equation, I think it shows degradation of available energy.

Rituraj said: (Jul 15, 2017)  
Entropy is an Index of unavailable and degradation of energy. So option D is correct.

Reshma said: (Jul 16, 2017)  
Entropy is property whch increase with temperature or head addition and decrease wit its removal.

Raghu said: (Jul 29, 2017)  
As entropy means a degree of randomness, so increase in entropy means that there is an increase in randomness. So, useful energy is degraded or lost.

For instance, suppose a boy has his books spread all over in his room, whereas, a girl has her books arranged in order. Therefore, we may say that the boy's room has more randomness and thus more entropy. So if I ask them to give me a history book (example), then the girl will be able to give me that book more quickly than the boy. So we may also conclude that the efficiency of the girl is more than that of the boy.

Hope, you've got the concept of entropy.

Shibashis said: (Dec 20, 2017)  
Nice example @Raghu.

Vikash Singh said: (Mar 11, 2018)  
Option B is incorrect because entropy can be increased even when heat is lost (or temp is decreasing) by internal irreversibility.

Option D is correct which is well explained by Raghu.

Rohit said: (Jun 11, 2018)  
Well explained @Raghu.

Dhananjay said: (Jan 21, 2019)  
Thanks @Raghu.

Anil Kumar said: (Jun 26, 2019)  
Answer D is correct because entropy means randomness of molecules. If the entropy will increase the degradation of energy will occur.

Gaurav said: (Dec 15, 2019)  
Agreed with D option.

Prasad Cln said: (Jun 23, 2020)  
The concept of Entropy mainly deals with the energy conversion (i.e. heat into work) and it's availability. This availability and non availability of the energy varies with the processes through which the system undergoes.

Here available energy is the work done (in a particular process) and non available energy is the internal energy stored in the system.

This brings a degree of randomness to the system. Thus the non availability degrades or reduces the interaction capability of the system with the surroundings. So the option "D" is the correct one.

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