Which type of valve allows flow to be shut off quickly by a small movement of a lever or other control?

The correct answer is a ball valve. This type of valve is specifically designed to allow for quick shut-off by rotating the lever or handle a quarter turn, which opens or closes a spherical disc inside the valve. This design enables the fluid to flow through the valve in a straight line when open, minimizing resistance and allowing for full flow.

The reason why a ball valve is preferred for situations requiring rapid control is due to its straightforward mechanism: when the lever is turned, the hole in the ball aligns with the flow, and when turned again, it blocks the flow almost instantly. This rapid operation is especially useful in applications where immediate shut-off is necessary.

In contrast, the other choices focus on different functionalities. For example, while a butterfly valve can also be used for quick shut-off, it typically requires a larger movement of the handle compared to a ball valve. A full flow valve is not a specific type of valve but rather a description of the characteristic of a valve that minimizes pressure drop. A check valve is designed to prevent backflow rather than to be used for quick shut-off.