Question

A frictionless piston-cylinder based enclosure contains some amount of gas at a pressure of $400 \,kPa$. Then heat is transferred to the gas at constant pressure in a quasi-sta ic process. The piston moves up slowly through a height of $10\,cm$. If the piston has a cross-section area of $0.3 \,m^2$, the work done by the gas in this process is

• A. 6 kJ
• B. 12 kJ
• C. 7.5 kJ
• D. 24 kJ

Answer 1

Answer: (B)

12 kJ

Answer 2

$W_{\text {constart pressure }} =p \times \Delta V$
$=400 \times 10^{3} \times 0.3 \times 10 \times 10^{-2}$
$=400 \times 10 \times 3$
$=12000=12 \,kJ$