ANS:E - all the above.

The magnitude of water hammer in a pipe depends on several factors:

1. Speed at which the valve is closed: When a valve in a pipeline is suddenly closed, the flow of water is abruptly stopped, causing a rapid change in velocity and pressure within the pipe. The faster the valve is closed, the greater the magnitude of the water hammer.
2. Length of the pipeline: The length of the pipeline affects the magnitude of water hammer. Longer pipelines provide more space for pressure waves to propagate, potentially increasing the magnitude of the water hammer effect.
3. Elastic properties of the pipe material: The elasticity of the pipe material plays a crucial role in determining how the pipe responds to sudden changes in pressure. Flexible pipes can absorb some of the shock caused by water hammer, reducing its magnitude, while rigid pipes may experience greater pressure surges.
4. Elastic properties of the flowing liquid: The compressibility and elasticity of the liquid flowing through the pipeline can influence the magnitude of water hammer. Liquids with higher compressibility or elasticity may experience more significant pressure surges during sudden changes in flow.