Which of the following instruments are used for measuring velocity? i. Hot water anemometer ii. Pitot tube iii. Orifice meter iv. Preston tube
- AOnly (i)
- BOnly (i) and (ii)Correct
- COnly (ii) and (iii)
- DOnly (iii) and (iv)
Solution
Concept
Instruments for measuring fluid velocity
Formula
NONE
Step-by-step solution
1. Hot wire anemometers and related instruments are used to measure flow velocity in fluid mechanics. 2. Pitot tubes, orifice meters, and Preston tubes serve different measurement functions in fluid dynamics. Answer: B
Explanation
Hot wire or water anemometers and Pitot tubes are standard devices used to measure fluid velocity in flow fields. In contrast, orifice meters measure total flow rate and Preston tubes determine wall shear stress. Therefore, statements i and ii are correct, making option B the right choice.
Why the other options are wrong
C) Orifice meter measures discharge rather than velocity. D) Orifice meter is used for measuring discharge, not flow velocity.
Shortcut
Orifice and Venturi meters measure discharge; Anemometer, Pitot, and Preston tubes measure velocity.
Common mistake
Confusing velocity measuring instruments with discharge measurement tools like orifice meters and selecting options containing (iii).
Correct answer: B) Only (i) and (ii)