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 path along which work done is least?

• A. ABC
• B. AC
• C. Equal for both
• D. None of the above

Answer 1

The correct option is B AC

For the path ABC $=W_{AB}+W_{BC}$
$=$ Area under $P-V$ curve
$=$ Area covered by line AB + Area of square below line BC
$0-15\times 4$
$=-60J$
For the path AC, $W_{AC}=$ Area occupied below line AC
$W_{AC}=-\left[\frac{1}{2}\right(5+15)\times (6-2\left)\right]$
$=-40J$
The work done along AC is the least.