Question

What is a device installed in a drainage system to prevent backflow?

1) Check valve
2) Overflow pipe
3) Sewer trap
4) Drain plug

Answer 1

A check valve is a device installed in a drainage system to prevent backflow. It allows water to flow in one direction but prevents it from flowing back in the opposite direction.

Step-by-step explanation:

A device installed in a drainage system to prevent backflow is a check valve. It is a one-way valve that allows water to flow in one direction but prevents it from flowing back in the opposite direction. When water flows through the drain, the check valve opens to allow the water to pass through, but when the water tries to flow back, the valve closes to prevent backflow.