Physics
Answer
In a water pump when the plunger is pulled up in the piston, there is no air inside and thus the pressure inside the siphon is much less than the atmospheric pressure acting on the liquid surface. As a result, the atmospheric pressure forces the water to rise up in the pump.
Related Questions
Illustrate with the help of a labelled diagram of a simple barometer that the atmospheric pressure at a place is 76 cm of Hg.
Explain how is the height of mercury column in the tube of a simple barometer, a measure of the atmospheric pressure.
Explain the following:
Two holes are made in a completely filled sealed tin can to take out oil from it.
Why does the liquid rise in a syringe when it's piston is pulled up ?