Question 37
Current ElectricityA calibrated potentiometer is used to measure the e.m.f. of a cell because the
- A.internal resistance of a cell is small compared with that of the potentiometer
- B.potentiometer has a linear scale
- C.potentiometer takes no current from the cell
- D.resistance of the potentiometer is less than that of a voltmeter.
Show the answer and explanation
Answer: C (potentiometer takes no current from the cell)
Explanation
At the balance point no current flows from the cell, so there is no voltage lost in its internal resistance and the true e.m.f. is measured.