Q1: The self-cleansing velocity of water flowing through pipe lines, is

ANS:A - 2 metres/sec

he correct self-cleansing velocity for water flowing through pipe lines is not 2 meters per second (m/s). In fact, it is typically around 0.5 to 1 meter per second (m/s). When water flows through a pipe, the velocity of the water affects its ability to transport suspended solids and prevent sedimentation and deposition along the pipe walls. If the velocity is too low, sediments may settle and accumulate, leading to reduced flow capacity and potential blockages. However, if the velocity is too high, it can cause excessive turbulence, erosion of pipe materials, and increased energy consumption. Therefore, an optimal velocity, usually in the range of 0.5 to 1 m/s, is maintained to ensure self-cleansing while minimizing the negative effects of high velocity flow.