Question in thermodynamics -- Two paths on a P-V diagram....

[Zouatine]

Homework Statement

thermodynamic

Relevant Equations

I think the answer is b , is that true ?

Hi every one , I have this question today :

The two arrows in the figure show two thermodynamic processes of a certain amount of ideal gas. The dashed line is a hyperbola. Which of the following statements is not true?

a. The heat transfer is the same in the two processes.
b. The temperature change is the same in the two processes.
c. The change in internal energy is the same in the two processes.

 

[jambaugh]

You need to post homework questions with your attempt at a solution so that you can be helped past the obstacles you have run across. This is not a forum where you can simply ask others to do your homework for you. Firstly it helps you not at all in discovering how to actually solve problems. Secondly it is against this forums policies.

 

[Mark44]

@Zouatine, as @jambaugh mentioned, you must show some effort.

 

[Chestermiller]

What is the basis for your choice of the answer as b?

 

[aliserwan]

i think a is correct

 

[Chestermiller]

i think a is correct

Correct!

 

[Bilbo B]

a isn't correct

 

[haruspex]

a isn't correct

Why?
Note: when you figure out the correct answer and reason, please do not post it in this thread just yet. Give time for @Zouatine to respond.

 

[Chestermiller]

a isn't correct

Wrong!

 

[aliserwan]

I found that Isothermal state :
delta T = 0
Delta U=0
then the correct answer is a
In Adiabatic state: transfer heat zero
True or False ??

 

[haruspex]

I found that Isothermal state :
delta T = 0
Delta U=0
then the correct answer is a
In Adiabatic state: transfer heat zero
True or False ??

No, there is a transfer of heat in both processes. What makes you think ΔT is zero? ΔP is zero in one, ΔV is zero in the other.
The question asks whether the same quantity is transferred,

 

[aliserwan]

One of the conditions of the case Isothermal : delta t =0

 

[aliserwan]

No, there is a transfer of heat in both processes. What makes you think ΔT is zero? ΔP is zero in one, ΔV is zero in the other.
The question asks whether the same quantity is transferred,

 

[Chestermiller]

I found that Isothermal state :
delta T = 0
Delta U=0
then the correct answer is a

Delta T and delta U are the same in both processes. But, they are not zero.

In Adiabatic state: transfer heat zero
True or False ??

This is the definition of an adiabatic process, so True. But what has this got to do with the present problem?

 

[aliserwan]

Delta T and delta U are the same in both processes. But, they are not zero.

This is the definition of an adiabatic process, so True. But what has this got to do with the present problem?

the present problem is Isothermal state
so delta T = 0
Delta U=0
then the correct answer is a

 

[Chestermiller]

the present problem is Isothermal state
so delta T = 0
Delta U=0
then the correct answer is a

Are you saying the delta T is zero for each of the two process paths? Or are you saying that delta T is zero between the two final states of the two processes?

 

[aliserwan]

Are you saying the delta T is zero for each of the two process paths? Or are you saying that delta T is zero between the two final states of the two processes?

i don't know exactly , However, do you agree with me that the correct answer is a

 

[Chestermiller]

i don't know exactly , However, do you agree with me that the correct answer is a

Even though a is the right answer, I mark you wrong on this problem because you were unable to provide an acceptable explanation.

 

[haruspex]

In that attachment, isothermal follows one of the curves. In the present problem, each process follows a straight line, one vertical, one horizontal. Neither is isothermal.

You seem to be thinking of a process that runs from one of those two final states to the other. That is not the question asked. You are asked to compare the two non isothermal processes.