Question

A thermodynamic process is shown in the following figure. The pressure and volumes corresponding to some points in the figure are :



$P_A=3\times {10}^{4}Pa,V_A=2\times {10}^{-3}{m}^3$
$P_B=8\times {10}^{4}Pa,V_D=5\times {10}^{-3}{m}^3$

In process AB, 600 J of heat is added and in the process BC, 200 J of heat is added to the system. The change in internal energy of the system in the process AC would be?

• A. 560 J
• B. 800 J
• C. 600 J
• D. 640 J

Answer 1

The correct option is A 560 J

$W_{AC}=W_{AB}=W_{BC}=0+8\times {10}^4(V_C-V_B)$
$=8\times {10}^4(V_D-V_A)=8\times {10}^4(3\times {10}^{-3})$
$=240$
$dO=dE+W_{AC}$
$800=dE+240$
$dE=560$