Answer: It draws no current from the source at balance.
- A It has a very high resistance along its entire length
- B It draws no current from the source at balance
- C It has a very low resistance along its entire length
- D It amplifies the voltage of the source being measured
Correct answer: B. It draws no current from the source at balance
Explanation: At balance, potentiometer draws zero current from the EMF source being measured: so it measures true EMF.
In series, the same current flows through both resistors; in parallel, the current splits between branches and the voltage across each resistor is the same.
Concept context
Ohm's law, resistors, Kirchhoff's laws, Wheatstone bridge, and cells.