Which of the following statements is/are true regarding Water Hammer? i. It is a sudden rise of pressure in a long pipe due to sudden closure of a valve. ii. It is developing of the negative pressure created due to the vacuum emerging from the sudden closure of a valve.
- AOnly (i)Correct
- BOnly (ii)
- CBoth (i) and (ii)
- DNeither (i) nor (ii)
Solution
Concept
Water hammer phenomenon in pipes
Formula
NONE
Step-by-step solution
1. Water hammer is a pressure surge created when a fluid in motion is suddenly forced to stop or change direction. 2. During transient flow caused by valve closure, pressure waves including negative pressure zones can be created. Answer: A
Explanation
Water hammer is defined as a rapid surge or rise in pressure that occurs when liquid flowing through a pipe is suddenly stopped by valve closure. It does not refer to the creation of negative pressure from a vacuum condition. Thus, statement i is true while statement ii is false, making option A correct.
Why the other options are wrong
C) Statement (i) is incorrect, so both statements cannot be true. D) Statement (ii) is true according to the given key.
Shortcut
Water hammer is a sudden positive pressure surge caused by rapidly closing a valve.
Common mistake
Believing that water hammer is defined by negative pressure vacuum creation rather than a sudden pressure rise wave.
Correct answer: A) Only (i)