Question

During an isothermal expansion, a confined ideal gas does 150 J of work against its surroundings. This implies that:

• A. 150 J of heat has been removed from the gas
• B. 300 J of heat has been added to the gas
• C. no heat is transferred because the process is isothermal
• D. 150 J of heat has been added to the gas

Answer 1

Answer: (D)

150 J of heat has been added to the gas

By first law of thermodynamics -

$dQ=dV+dW$

$dV=0$ for isothermal process

$dQ=dW$

$=+150$

$\Rightarrow 150J$ of heat has been added to the system.

So, the correct answer is '150 J of heat has been added to the gas'.