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GATE 2022 BM – Question 28

Sensors and Bioinstrumentation · Electrical Isolation and Safety · 1 mark · Multiple select

Which biomedical-instrument electrical-safety statements are true?

  1. Let-go current is the maximum current at which a person can withdraw voluntarily
  2. Microshock is a physiological response to electrical current passing through the heart
  3. An ICU patient with internal conductive electrodes near the heart is exposed to microshock danger
  4. The safe 50 Hz microshock current limit is greater than 50 mA

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Show answer and explanation

Correct answer: (A) Let-go current is the maximum current at which a person can withdraw voluntarily; (B) Microshock is a physiological response to electrical current passing through the heart; (C) An ICU patient with internal conductive electrodes near the heart is exposed to microshock danger

Explanation

A correctly defines the let-go threshold. B identifies direct cardiac-current microshock, and C describes the conductive pathway that can bypass protective skin impedance. D is false: direct cardiac exposure is hazardous at currents far below tens of milliamperes. Correct choices A,B,C. These are conceptual statements from the exam, not operating limits for equipment.