Question

Shown below are the vertical cross-sections of handpumps. Which of the following options depict(s) the correct working principle?

• A.

  

• B.

  

• C.

  

• D.

  

Answer 1

The Correct Option is A, B

Step 1: Recall the principle of handpumps. 
Atypical handpump works on the principle of atmospheric pressure and piston action:- The piston moves up and down.- Two valves (one at the bottom and one in the piston) ensure unidirectional water flow.- Upward motion of the piston creates suction, drawing water into the cylinder.- Downward motion closes the lower valve and allows water to pass through the piston valve, filling the upper chamber. 

Step 2: Analyze the diagrams. 
(A): Correctly shows the piston pulling water up. (B): Correctly shows the piston pushing water through the piston valve. (C): Misaligned valve mechanism, water cannot rise properly. (D): Incorrect configuration of valves, water path is blocked. 

Correct options: (A) and (B).