Which of the following statement(s) is/are true regarding Pitometer? (i) It is an instrument that measures the velocity of a flowing liquid or gas by sensing pressure differences. (ii) It consists of dual Pitot tubes – one upstream and one downstream – that translate fluid pressure into a velocity reading
- AOnly (i)
- BOnly (ii)
- CBoth (i) and (ii)Correct
- DNeither (i) nor (ii)
Solution
Concept
Pitometer flow velocity measurement
Formula
v = C × √(2 × g × Δh)
Step-by-step solution
1. A Pitometer is a modified Pitot device used in flow velocity surveys, confirming (i). 2. It incorporates two orifices in a single rod: an upstream dynamic impact tip and a downstream wake suction tip, confirming (ii). 3. The differential pressure across the orifices corresponds to local flow velocity. 4. Hence, both statements (i) and (ii) are true. Answer: C
Explanation
A Pitometer is a differential-pressure velocity measuring instrument consisting of dual Pitot orifices facing directly upstream and downstream in a pipe. The upstream orifice measures stagnation pressure while the downstream orifice measures wake pressure, and the differential head across a manometer directly relates to flow velocity.
Why the other options are wrong
A) Incomplete because statement (ii) accurately describes its dual-tube construction. B) Incomplete because statement (i) correctly defines its velocity measurement capability. D) Both statements are true.
Shortcut
Pitometer = Dual Pitot tube (facing upstream and downstream) measuring flow velocity.
Common mistake
Assuming a Pitometer measures volumetric flow directly rather than velocity head.
Correct answer: C) Both (i) and (ii)