Red Seal Electrician Practice
Motor controlsQuestion 252 of 1506

Where are the source and the detector of a nuclear level switch mounted?

  1. Buried in the material near the top
  2. Inside the vessel, on a floating ball
  3. On the same side as a paddle wheel
  4. Outside the vessel, on opposite sides of it
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Correct answer: Outside the vessel, on opposite sides of it

The radiation passes through the vessel. More material in its path weakens the radiation that reaches the detector.

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

Practice motor controls

Questions last reviewed: 18 October 2026