Mechanical Engineering - Thermodynamics - Discussion


There is a loss of heat in an irreversible process.

[A]. True
[B]. False

Answer: Option A


No answer description available for this question.

Bhagat Viijay said: (Jun 27, 2013)  
In reversible process due to friction and irregularities the heat is released.

Pasupathyram said: (Jul 10, 2013)  
Irreversible process or natural process is open to atmosphere. The process can't reach final position. Example: the sun.

Mayank Agrawal said: (Sep 1, 2013)  
Cyclic process are also irreversible in nature and in cyclic process there is no loss of heat energy due to the first law.

Lakshmi said: (Sep 5, 2013)  
Amount of heat loss is proportional to irriversability.

Sairam said: (Sep 22, 2013)  
Irreversibility is occurs due to Heat transfer through a finite temperature difference in a process.

Thirupathi Malavath said: (Sep 29, 2013)  
Irreversibility can be defined mathematically as a product of Surrounding Temperature(T) and change in entropy of the universe(ds) , which means loss of energy in the form of heat.

.Ajay And Rakesh said: (Dec 20, 2013)  
C = dQ/dT.

The amount of heat required to raise the temperature of substance through one degree celsius is called specific heat. If the process occurs at constant volume is called specific heat at constant volume.

Aashish said: (Jan 4, 2014)  
All above are wrong. Actually in irreversible process available energy decreased which makes the system to lose energy in form of heat.

Pratik Adhav said: (Jan 8, 2014)  
I = Tods-dq.

Irreversible process does not go to completion, so that there is a loss in this process.

Chavda said: (Jan 12, 2014)  
In an irreversible process, finite changes are made; therefore the system is not at equilibrium throughout the process.

Varma said: (Jan 13, 2014)  
Irreversible process is always accompanied by the increase in entropy.

Sushant said: (Feb 11, 2014)  
Amount of heat loss is proportional to irreversibility.

Najin K said: (Mar 16, 2014)  
It is not always true. Ex- let us consider an insulated container (system) having two gases with a finite pressure difference separated by a partition. Removing the partition will result in an irreversible process due to finite pressure difference.

But in this case there is no heat transfer as the system is insulated. So, an irreversible process not necessarily result in heat loss.

Parveen Kumar said: (Apr 22, 2014)  
In reversible process heat can change in this process apple thermodynamic first law. Heat can not created or not destroyed when any process go reversible this heat chang due to some friction and some surrounding loss heat.

Vishnu said: (May 10, 2014)  
If any process is done there may be loss of energy (heat). Such that in irreversible process heat is released & we cannot collect it. Hence in irreversible process heat is loss.

S.Ramasamy said: (Jul 27, 2014)  
Irreversible is adiabatic process.

Kartikeswar Rana said: (Aug 2, 2014)  
In irreversible process heat is generated by friction. So answer is A.

Yadunandan Nagar said: (Aug 30, 2014)  
Irreversible is a isentropic process so in this process is heat loss.

J Bhargavi Baaji said: (Sep 3, 2014)  
Reversible is a closed process there will be no heat loss and can reach to the final position where as in irreversible process it cannot reach to its final position as it is open process and heat loss occurs.

Lavlesh Mishra said: (Oct 1, 2014)  
Friction is Main causes of irreversibility.

Devan said: (Nov 25, 2014)  
Due to entropy generation.

Biswaranjan Biswal said: (Feb 1, 2015)  
A process is said to be irreversible when it doesn't come back to its original state. So their must be some energy losses and heat is also a form of energy.

Rohit Kumar said: (Mar 21, 2015)  
In irreversible process, there is a loss of heat due to friction, radiation, or conduction.

Ankit Singh said: (Mar 27, 2015)  
It's a contradictory question. Both answer is possible.

Let's take an example. A gas chamber is subdivided by partition and suddenly partition is removed and it is insulated. It's example of irreversibly but more closet answer is option A.

Nagu said: (Jul 4, 2015)  
In irreversible process some losses will takes places for example man walk in forward direction is easy but in reverse direction little difficult.

Prashant Raturi said: (Jul 5, 2015)  
Hello friends.

The correct answer is FALSE,


For irreversible process change in entropy will be greater than 0, and as we know that entropy generation is always +,

And for no heat loss the quantity int (dq/T) will be 0 but due to entropy generation change will be +.

Sumit said: (Aug 7, 2015)  
There is no loss of heat but available energy in irreversible process.

Gaurav said: (Sep 20, 2015)  
In this if temperature difference is very negligible between two bodies then heat lose very slow and process become reversible. But in these bodies having considerable temperature difference then heat lose become fast and process become irreversible. So in these case both answer is possible.

Gaurav said: (Sep 20, 2015)  
(1) For example heat lose b/w body a 500 k and body b 1000 k.

(2) Heat lose b/w body c 300 k and body d 500 k. So process 1 more irreversible then process 2.

(3) For ex heat lose b/w body h 500 k and body I 499.999 k temperature.

Here process 3 is reversible because process is very slow.

So in this question both answer is possible.

Praveen S said: (Jun 11, 2016)  
The isentropic process is a reversible adiabatic process.

In an reversible process pressure remains unchanged.

In adiabatic process there is no heat transfer between the system and the surroundings.

Pritam said: (Aug 11, 2016)  
According to inequality of Clausius.

dq/dt < 0 for irreversible process.

This shows that change in heat is always negative i.e. heat loss in the irreversible process.

Hemesh Kumar said: (Aug 12, 2016)  
An irreversible process is a non-quasistatic process which is a fast process in comparison to quasistatic process and the fast process has affected the surrounding around them means loses some energy in the form of friction or heat or in any other type.

For ex- wheel of automobile release some energy on the road (surrounding) in the form of friction and heat which is useless after reaching in the surrounding.

Except Carnot cycle, every process is losses heat or energy without any loss no real process exists in nature.

Hemesh Kumar said: (Aug 12, 2016)  
1. If we want without any loss (heat) process then it will only reversible process which is a very slow process.

2. We can understand it by taking the example of piston-cylinder arrangement. In this according to irreversible process piston move in a cylinder with some speed, if speed I'd high than heat is a loss, therefore, it is an irreversible process and due to irreversible heat is lost.

On the other hand, heat is not lost when the process is very slow means one stroke of the piston is done in like one hour, one day, one month which is useless for any mechanism.

Adarsh Mishra said: (Mar 15, 2017)  
Every spontaneous process is irreversible (flowing water stream across finite potential difference) but there is no loss of HEAT.

All irreversible process are accompanied by loss of EXERGY (availability) instead.

K.Nikhil said: (Sep 7, 2017)  
In thermodynamics, reversible process is know as quize static process. Irreversible process means we can't get the same amount of energy when we reverse the process. So amount of heat loses through the surroundings.

Chandrasekhar said: (Sep 12, 2017)  
In thermodynamics, reversible process is know as quize static process. Irreversible process means we can't get the same amount of energy when we reverse the process.

Nachimuthu said: (Sep 14, 2018)  
Reversible process are cv, cp, ct process.

Irreversible process are throttling process and free expansion process.

Anonymous said: (Jan 5, 2019)  
An irreversible process is always accompanied by an increase in entropy. This will result in heat loss.

Even in the case of the adiabatic irreversible process though there is no heat loss due to external irreversibility,

But internal irreversibility will lead to heat loss.

Mohit said: (Sep 27, 2019)  
Heat transfer through a finite temperature gradient leads to irreversibility. But there is no heat loss.

Another example is irreverible adiabatic process. NO heat loss is there. I think the Answer should be B.

Jithindas said: (Nov 9, 2020)  
During this transformation, there will be some heat energy loss or dissipation due to intermolecular friction and collisions. This energy will not be recoverable if the process is reversed.

Post your comments here:

Name *:

Email   : (optional)

» Your comments will be displayed only after manual approval.