Question

One mole of Helium gas undergoes a reversible cyclic process ABCDA as shown in the figure.
Assuming gas to the ideal, answer the following questions:

What is the net work involved in the process A to C?

• A. $-100R(1-\text{ln}8)$
• B. $300\text{R ln2 J}$
• C. $-100R(1+\text{ln}8)$
• D. $200\text{J}$

Answer 1

Answer: (A)

$-100R(1-\text{ln}8)$

${\omega }_{A\to C}={\omega }_{A\to B}+{\omega }_{B\to C}$
$=-1\times R\times 300ln\left(\frac{1}{2}\right)+[-2atm(V_C-V_B\left)\right]$
$=300Rln2+1\times R\times [T_B-T_C]$
$=300Rln2-100R$
$=-100R[1-3ln2]$
$=-100R[1-ln8]$