Question

A pump is used to transport water from a reservoir at one elevation to another reservoir at a higher elevation. If the elevation difference increases by four times, the pump power required:
A) Increases by two times

B) Increases by four times

C) Increases by eight times

D) Increases by sixteen times

Answer 1

Answer:b

Explanation:

We know power delivered by Pump is

$P=\rho \times Q\times g\times \Delta H$

where $P\rho$=Density of fluid

$Q$=Flow rate

$g$=acceleration due to gravity

$\Delta H$=Change in Elevation

If $\Delta H$ is increased by 4 time then

$P'=\rho \times Q\times g\times (4\Delta H)$

$P'=4 P$

So power increases by four times.