Question

An ideal gas expands along the path $AB$ as shown in the $p-V$ diagram. The work done is :

• A. $4J$
• B. $1.2J$
• C. $2.4J$
• D. $0.8J$

Answer 1

Answer: (B)

$1.2J$

From figure, we get $BC=8$ Pa $AD=4$ Pa $CD=0.2$ $m^3$

Area under the p-V graph gives the work done by the gas.

Thus work done $W=$ Area of trapz(ABCD) $=\frac{1}{2}[AD+BC]\left(CD\right)$

$\therefore$ $W$ $=\frac{1}{2}[4+8]\left(0.2\right)=1.2Pa{m}^3=1.2$ $J$