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JAMB Physics 1999 Question 12

Question 12

Pressure

The diagram above shows a lift pump with valves at P and Q. During a downward stroke of the piston

Diagram for this question
  1. A.both valves are open
  2. B.P is open while Q is closed
  3. C.P is closed while Q is open
  4. D.both valves are closed.
Show the answer and explanation

Answer: B (P is open while Q is closed)

Explanation

On the downstroke the water below the piston is pushed up: it closes the bottom valve Q and opens the piston valve P so the water passes above the piston.