Question

Find the power of a pump which takes $10\text{s}$ to draw $100\text{kg}$ of water from a tank situated at a height of $20\text{m}$.
(correct answer + 1, wrong answer - 0.25)

• A. $2\times {10}^4\text{W}$
• B. $2\times {10}^3\text{W}$
• C. $200\text{W}$
• D. $1\text{kW}$

Answer 1

The correct option is B $2\times {10}^3\text{W}$

$\text{Power}=\frac{\text{Work}}{\text{Time}}=\frac{mgh}{\text{time}}$
$=\frac{100\times 10\times 20}{10}=\frac{20000}{10}$
$=2000$ i.e., $2\times {10}^3\text{W}$