Question

An electric pump takes $30$ minutes to fill a tank of volume $30m^3$ with water. If the height over which the water is lifted be $30m$, and the efficiency of the pump is $50\%$, the input electric power required by the pump is:

(Given $g=10m/$$s^2$)

• A. $100000W$
• B. $10000W$
• C. $1000W$
• D. $100W$

Answer 1

The correct option is B $10000W$

$1$ meter cube water weighs $1000kg$, so $30$ meter cube of water weighs $30,000kg$
Time, $t=30\times 60sec$
$h=30m$
$g=10m/s^2$

Efficiency of pump is $50\%$.

So, $0.5P=\frac{mgh}{t}$

Putting these values we get,
$P=10000W$