In a water tap, how is water flow stopped?

The most suitable answer to how water flow is stopped in a water tap is the disc with a washer. This mechanism typically involves a washer that sits against a seat or surface within the tap. When the tap is turned off, the disc with a washer presses against the seat, effectively sealing the opening and preventing any water from flowing through.

This design ensures a tight closure, minimizing leaks and allowing for precise control over the water flow. The washer material, often rubber or a similar substance, enhances the effectiveness of this seal, providing a reliable mechanism to halt water flow when needed.

Other options, while related to the functioning of taps, do not specifically reflect the primary method by which water is halted. For instance, a valve generally refers to a broader category of devices used to control fluid flow in various plumbing applications, while a valve spindle usually refers to the component that regulates the movement of the valve rather than being the direct mechanism for halting flow. The term "screw spindle" is less commonly associated with standard taps and does not convey the same functional role in stopping the flow of water. Thus, the design involving the disc with a washer is the most effective and appropriate answer for stopping water flow in this context.