State the advantages of potentiometer over voltmeter.
Advantages of potentiometer over voltmeter:
a. The voltmeter is used to measure terminal P.D of cell while potentiometer is used to measure small terminal P.D as well as e.m.f of the cell.
b. The accuracy of potentiometer can be easily increased by increasing the length of wire.
c. A small P.D can be measured accurately with the help of potentiometer. The resistance of voltmeter is high but not infinity to work as an ideal voltmeter.
d. The internal resistance of a cell can be measured with the help of potentiometer.
e. Potential difference across the wire is greater than E1 or E2 or E1 + E2.