Q91 / 180 · JIPMER 2018 · Physics

If a machine perform 4000 J output work and 1000 J is inside loss due to friction, then the find efficiency?

  • Correct answer
    A
    $80 \%$
  • B
    $30 \%$
  • C
    $25 \%$
  • D
    $60 \%$

Solution

$\because$ Efficiency $=\frac{\text { output work }}{\text { input work }} \times 100=\frac{\mathrm{W}_{\mathrm{o}}}{\mathrm{W}_{\mathrm{i}}} \times 100$ $\begin{aligned} & \because \mathrm{W}_{\mathrm{o}}=4000 \mathrm{~J} \\ & \therefore \mathrm{W}_{\mathrm{i}}=4000+1000=5000 \mathrm{~J} \\ & \therefore \text { Efficiency }=\frac{4000}{5000} \times 100=80 \%\end{aligned}$

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

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