Question

$20$ litre of an ideal gas, present in a piston fitted cylinder at $10$ atm is allowed to expand in a process in which $P/V$ is a constant. If final volume of gas is $60$ litre, then work done by gas is:

• A. $81.12kJ$
• B. $-81.12kJ$
• C. $40.56kJ$
• D. $-40.56kJ$

Answer 1

The correct option is D $-40.56kJ$

$W=-P(V_2-V_1)$

$=10(60-20)$

$=10\left(40\right)=-400atmL$

$1atm=101325Pa$

$\Rightarrow 1atm=101325J/m^3$

$\Rightarrow 1L={10}^{-3}{m}^3$

$\therefore W=400\times 101325\frac{J}{M^3}\times {10}^{-3}{M}^3$

$=-40.56kJ$