Q111 / 200 · NEET 2011 (Screening) · Physics

During an isothermal expansion, a confined ideal gas does $150 \mathrm{~J}$ of work against its surroundings. This implies that

  • A
    $300 \mathrm{~J}$ of heat has been added to the gas
  • B
    no heat is transferred because the process is is othermal
  • Correct answer
    C
    $150 \mathrm{~J}$ of heat has been added to the gas
  • D
    $150 \mathrm{~J}$ of heat has been removed from the gas

Solution

By first law of thermodynamics - $$ \begin{aligned} \mathrm{dQ} & =\mathrm{dV}+\mathrm{dW} \\ \mathrm{dV} & =0 \text { for isothermal process } \\ \mathrm{dQ} & =\mathrm{dW} \\ & =+150 \end{aligned} $$ $\Rightarrow 150 \mathrm{~J}$ of heat has been added to the system. So, the correct answer is ' $150 \mathrm{~J}$ of heat has been added to the gas'.

Hence, the correct answer is option: 'C'.

Relevant Questions