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GATE 2024 BM – Question 43

Sensors and Bioinstrumentation · Physiological Measurements · 2 marks · Multiple choice

In the shown pressure catheter–diaphragm sensor, liquid resistance RL arises from viscous friction. Only catheter radius is doubled, with pressure difference fixed. What happens to RL?

Diagram for GATE 2024 BM question 43
  1. Decreases by factor 16
  2. Decreases by factor 8
  3. Decreases by factor 4
  4. Decreases by factor 2

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Show answer and explanation

Correct answer: (A) Decreases by factor 16

Explanation

For laminar flow in a circular catheter, Poiseuille resistance is RL=8μL/(πr⁴). Holding fluid and length fixed, doubling radius multiplies r⁴ by sixteen, so resistance becomes RL/16. Thus A. Fixed pressure difference changes flow rate accordingly.

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