Red Seal Electrician Practice
Motor controlsQuestion 253 of 1506

How does a tuning-fork level switch sense that a bin is full?

  1. The material damps the fork's vibration
  2. The material stops a slow paddle wheel
  3. The material closes two metal probes
  4. The material blocks a beam of light
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Correct answer: The material damps the fork's vibration

An electronic circuit vibrates the fork and watches the vibration. Material at that height damps it.

Source: Lessons in Electric Circuits IV: Digital (Kuphaldt), 4.1: Switch Types

Practice motor controls

Questions last reviewed: 18 October 2026