Why is a potentiometer preferred over a voltmeter for determining the e.m.f. of a cell?

Explain the principle on which the working of a potentiometer is based. Why is the use of potentiometer preferred over that of a voltmeter for measuring the e.m.f. of a cell.

Name the device used for measuring the e.m.f. of a cell.

In a potentiometer arrangement for determining the emf of a cell, the balance point of the cell in open circuit is 350 cm. When resistance of 9 Omega is used in the external circuit of the cell, the balance point shifts to 300 cm. Determine the internal resistance of the cell.

Why paracetamol is preferred over aspirin?

It is found that 125 cm length of a potentiometer wire is required to balance the e.m.f. of a Daniel cell but that only 100 cm of the wire is required for the balance, if the poles of the ell are joined to a resistance of 2 ohm. Calculate the internal resistance of the cell.

What is electrochemical series? How it used to determine the e.m.f. of the cell?

A cell of e.m.f. 4 V and of negligible internal resistance is connected in series with a potentiometer wire of length 400 cm. The e.m.f. of a Leelanche cell is found to be balacned at 150 cm from the positive end of the potentiometer wire. What is the e.m.f. of the Leclanche cell ?

Explain the principle of a potentiometer. How will you compare the e.m.f. of two primary cells by using potentiometer? Explain with proper circuit diagram.