Question

The given figure shows a change of state A to state C by two paths ABC and AC for an ideal gas. Calculate the internal energy at C if the internal energy of gas at A is 10 J and amount of heat supplied to change its state to C through the path AC is 200 J.

• A. 170 J
• B. 200 J
• C. 160 J
• D. 40 J

Answer 1

The correct option is A 170 J

According to Ist law of thermodynamics, for the path AC
$q=\Delta U-w$
or $\Delta U=q+\left(w\right)=200+(-40)=160J$

or $U_C-U_A=160J$
${\therefore U}_C=160+10=170J(\because U_A=10J)$