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Current Electricity — Physics STD 12 Science — Question

Bihar BoardEnglish MediumSTD 12 SciencePhysicsCurrent Electricity1 Mark
MCQ
 Potentiometer measures potential more accurately because
  • A
    it measures potential in the open circuit.
  • B
    it uses sensitive galvanometer for null deflection.
  • C
    it uses high resistance potentiometer wire.
  • D
    it measures potential in the closed circuit.
✓

Answer

  1. it measures potential in the open circuit.

Explanation:

A potentiometer has very large resistance. To read load voltage or voltage across any circuit element, potentiometer is connected parallel across it. Thus, the load voltage or circuit voltage gets applied across the potentiometer but as the resistance is very high compared to load resistance, you can safely assume their is almost no current flowing through potentiometer. As power = VI, the power loss in potentiometer is almost equal to zero as current through it remains zero.

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