Q1: __________ joint is mostly used for joining pipes carrying water at low pressure.

ANS:B - Socket

The joint mostly used for joining pipes carrying water at low pressure is the Socket joint. Explanation:

1. Nipple Joint: Nipple joints are typically used for connecting two pipes or fittings end-to-end. They are commonly used in plumbing systems for specific purposes but are not typically used for joining pipes carrying water at low pressure.
2. Socket Joint: Socket joints involve connecting pipes by inserting one end into a socket or opening of another pipe or fitting. This joint provides a secure connection and is widely used for joining pipes carrying water at low pressure in residential, commercial, and industrial plumbing systems.
3. Union Joint: Union joints consist of three parts: a female end, a male end, and a nut. They allow for easy disassembly of the joint without disturbing the pipes. While union joints offer convenience for maintenance and repairs, they are less commonly used than socket joints for joining pipes carrying water at low pressure.
4. Bell and Spigot Joint: Bell and spigot joints are typically used for joining larger diameter pipes, such as sewer pipes or drainage pipes. They involve a bell-shaped opening on one pipe and a spigot (male end) on the other pipe, which fit together to form a tight seal. While bell and spigot joints are suitable for certain applications, they are less common in low-pressure water piping systems compared to socket joints.