Question

1. (a) figure 14 shows a lift pump.

explain why when the piston is:
(i) pulled upwards, valve a opens while valve b closes.
(2 marks)
(ii) pushed downwards, valve a closes while valve b opens.
(2 marks)

Explanation:

(i) When the piston is pulled upwards, the space below it expands, lowering pressure. Atmospheric pressure pushes valve A open (allowing water in) and keeps valve B closed (since pressure above B is higher than below).
(ii) When pushed downwards, pressure below the piston increases. This closes valve A (higher pressure below A) and pushes valve B open (water flows through B).

Answer:

(i) Upward piston pull lowers pressure below it; atmospheric pressure opens A, closes B.
(ii) Downward push increases pressure below piston; closes A, opens B.