Correct statement about thermodynamics process

[songoku]

Homework Statement

An ideal gas is taken through two cycles shown in Figure a and b. In Figure a, the cycle consists of process A (solid line) and adiabatic process (dash line). In figure b, the cycle consists of process B (solid line) and isothermal process (dash line). Which of the following statements is true?
A) The heat of both processes A and B are released;
B) The heat of both processes A and B are absorbed;
C) The heat of process A is released, while the heat of process B is absorbed;
D) The heat of process A is absorbed, while the heat of process B is released.

Relevant Equations

ΔU = Q + W

I know process B absorbs heat but I can't determine the heat of process A.

In adiabatic process, Q = 0 but process A is not adiabatic. I only know both W and ΔU will be negative for process A but how to know Q?

Thanks

 

[Chestermiller]

What is the value of $\Delta U$ when a gas undergoes a thermodynamic cycle, starting and ending in exactly the same thermodynamic state?

 

[songoku]

What is the value of $\Delta U$ when a gas undergoes a thermodynamic cycle, starting and ending in exactly the same thermodynamic state?

ΔU will be zero since there is no change in temperature. But sorry I don't understand the direction of the hint since process A does not start and end in exactly same thermodynamic state.

Thanks

 

[Chestermiller]

For process A, I think they mean the entire cycle, not just the solid line. I think it also includes the dashed line.

 

[kuruman]

For process A, I think they mean the entire cycle, not just the solid line. I think it also includes the dashed line.

I think they mean the solid line. Please see below.

ΔU will be zero since there is no change in temperature. But sorry I don't understand the direction of the hint since process A does not start and end in exactly same thermodynamic state.

For process A, write the first law for the dashed and solid line:

$\Delta U_A^{\text{solid}}=Q_A^{\text{solid}}+W_A^{\text{solid}}$

$\Delta U_A^{\text{dashed}}=Q_A^{\text{dashed}}+W_A^{\text{dashed}}$

You know that $\Delta U_A^{\text{solid}}=\Delta U_A^{\text{dashed}}$

What else do you know?
How do $W_A^{\text{solid}}$ and $W_A^{\text{dashed}}$ compare?

Repeat along similar lines with process B asking yourself the same questions.

 

[songoku]

I understand.

Thank you very much for the help and explanation Chestermiller and kuruman