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SarkariResultOutBMS · 2024

Previous Year Question

Choose the correct option about Pitot tube employed in fire-fighting system. Statement-1: This is an instrument for the measurement of water velocity pressure. Statement-2: This can be used to determine approximate amount of water flowing with the help of size of opening (orifice/nozzle) and water velocity pressure.
  1. Both statements are True
  2. Statement-1 is True, but Statement-2 is False
  3. Statement-1 is False, but Statement-2 is True
  4. Both statements are False

Correct answer: A

Explanation

A pitot tube measures velocity pressure in a water jet. Using that pressure to determine jet velocity and combining it with the known nozzle/orifice area allows approximate discharge to be calculated. Therefore both statements are true, corresponding to option A.

Formula

v≈√(2Δp/ρ); Q≈A v

Step-by-step solution

Velocity Pressure and Flow Estimation explanatory diagram

Correct Answer

A — Both statements are True

Statement-wise Analysis

Statement 1: True

Statement 2: True

Concept and Reasoning

A pitot tube measures velocity pressure in a water jet. Using that pressure to determine jet velocity and combining it with the known nozzle/orifice area allows approximate discharge to be calculated. Therefore both statements are true, corresponding to option A.

Calculation / Key Relation

v≈√(2Δp/ρ)

Q≈A v

Exam Takeaway

Pitot pressure → velocity → flow when nozzle area is known.

Common Mistake

The pitot tube does not directly measure volumetric flow without outlet geometry.

Common mistake

The pitot tube does not directly measure volumetric flow without outlet geometry.

Exam tip

Pitot pressure → velocity → flow when nozzle area is known.

Quick method

Pitot pressure → velocity → flow when nozzle area is known.