Q14 / 150 · MHT CET 2023 (11 May Shift 1) · Chemistry

What is the value of increase in internal energy when system does $8 \mathrm{~J}$ of work on surrounding by supplying $40 \mathrm{~J}$ of heat to it?

  • A
    $23 \mathrm{~J}$
  • Correct answer
    B
    $32 \mathrm{~J}$
  • C
    $40 \mathrm{~J}$
  • D
    $48 \mathrm{~J}$

Solution

Heat $(Q)=+40 \mathrm{~J}$ Work $(W)=-8 \mathrm{~J}$ According to first law of thermodynamics, $$ \begin{aligned} & \Delta \mathrm{U}=\mathrm{Q}+\mathrm{W} \\ & \Delta \mathrm{U}=(+40-8) \mathrm{J} \quad \therefore \quad \Delta \mathrm{U}=+32 \mathrm{~J} \end{aligned} $$

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

Relevant Questions