Mechanical Engineering - Thermodynamics - Discussion

Discussion Forum : Thermodynamics - Section 2 (Q.No. 1)
1.
According to Kelvin-Planck's statement of second law of thermodynamics,
it is impossible to construct an engine working on a cyclic process, whose sole purpose is to convert heat energy into work
it is possible to construct an engine working on a cyclic process, whose sole purpose is to convert heat energy into work
it is impossible to construct a device which operates in a cyclic process and produces no effect other than the transfer of heat from a cold body to a hot body
none of the above
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
14 comments Page 1 of 2.

Atanu said:   3 years ago
It is Impossible to Construct a heat engine which will give no other effect except to extract heat from a single reservoir and to equal ammount of work .

H.E
Q rej. =0.
Q add =W net.

Thermal efficiency n = W/Q add =1.
n= 100%,

So answer is A correct.

Sunil Sachdeva said:   5 years ago
I agree @Subhashree.

Let us take an example of a Steam Turbine (as Heat Engine) It 's exhaust Steam give it's residual heat to Condenser. Heat exchange is not limited to Condenser, since Condenser's heat is taken away by Cooling Water/ Atmospheric Air.

Subhashree said:   5 years ago
It impossible to construct a heat engine which work cyclically and exchange heat with a single fix reservoir.

100% conversion of heat into work in a heat engine is not possible.

Mano said:   6 years ago
I think the answer is C.

Sarath said:   6 years ago
In option C, "device" is wrong it should be written as "engine".

So that it become wrong. And both A and C are right.

Nikhil said:   6 years ago
According to me, the correct answer is c.

Robin parihar said:   7 years ago
Impossible to make an engine whose efficiency is 100%.

Manoj said:   7 years ago
The meaning of statement :

1. It is impossible to make a such engine which thermal efficiency is 100%.

T.E = W.D/Heat supplied.

2. All practical engine are irreversible.

3. PMM2 type machine not possible.

Malli said:   8 years ago
It is impossible because of have a single reservoir.

Busa Sravan Kumar said:   8 years ago
It is impossible to construct a device which works on a cycle and exchange heat with a single reservoir. It means with only one reservoir we can't exchange heat if there is only one reservoir it means whole heat energy we are giving is converted into 100% work it is not possible. It became the violation of kelvin-plank statement.


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