Mechanical Engineering - Thermodynamics - Discussion

Discussion Forum : Thermodynamics - Section 1 (Q.No. 9)
9.
When the gas is heated at constant volume, the heat supplied increases the internal energy of the gas.
True
False
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
27 comments Page 2 of 3.

Manoj said:   1 decade ago
But w= pdv is true only for reversible process.

Dr. Aayush Gupta and Dr. Rajkiran Shrivastav said:   1 decade ago
Since we have considered a reversible process and closed system, in which work done = pdv, but at constant volume pdv work done is zero.

By first law of thermodynamics we have,

q = du + w,
therefore q=du.

Purusottam said:   1 decade ago
In constant volume process change in volume is zero. So boundary work Pdv is zero. from first law,

dq=du+dw, dw=0.

So dq=du, hence heat supply increases internal energy.

Rakesh Kumar Maurya said:   1 decade ago
Constant volume means, no work obtained by object because of volume change is not possible by internal energy change.
(1)

Uttam kumar said:   1 decade ago
I can't understand que. In case of inter energy, they get increase but how the supplied energy get increase?

Uttam kumar said:   1 decade ago
Collision between the atoms also be responsible for increase in internal energy. If external energy are supplied.

Amar Dev said:   1 decade ago
Heat supplied = Work done + Change in internal energy.

dQ = W + dU.

dQ = PdV + dU [dV(change in volume) = 0 in case of constant volume].

So dQ = dU.

Anil said:   1 decade ago
No pressure change means no work. In this case heat supplied is =internal energy. From 1st law.

ROHIT KUMAR said:   1 decade ago
We know that in constant volume process volumes remain constant. So work done = 0.

Now,

DQ = dU+DW.
DW = 0.
So DQ = dU.

So heat supplied in constant volume process is used to increase it's internal energy.

Kunwar singh said:   1 decade ago
If we heat at a constant volume then W=O.

And according to thermodynamics first law:

dQ = dU+dW.
dQ = dU.

Then it heat supplied will be increase then it internal energy automatically increase because it final temperature will be increase.


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