A valve which allows the water to flow in one direction but prevents its flow in the reverse direction is known as
- ASluice valve
- BReflux valveCorrect
- CAir relief valve
- DPressure relief valve
Solution
Concept
A reflux valve (check valve or non-return valve) allows flow in only one direction.
Step-by-step solution
1. A sluice valve controls or stops flow in a pipe. 2. An air relief valve removes trapped air at summits. 3. A pressure relief valve releases excess pressure. 4. A reflux valve stops reverse flow, so the answer is B.
Explanation
A reflux valve is also called a check valve or non-return valve. It opens for forward flow and closes automatically when flow reverses. It is used near pumps to stop back flow.
Why the other options are wrong
A: Sluice valve regulates or stops flow in both directions. C: Air relief valve releases accumulated air. D: Pressure relief valve releases excess pressure.
Shortcut
Reflux = no return flow (non-return valve).
Common mistake
Choosing sluice valve, which only controls flow and does not stop reverse flow.
Correct answer: B) Reflux valve