Question

A potentiometer wire is 4m long and potential difference of 3V is maintained between the ends. The emf of the cell, which balances against a length of 100 cm of the potentiometer wire is ____________.

Options

• 0.60 V

• 0.50 V

• 0.25 V

• 0.75 V

Answer 1

A potentiometer wire is 4m long and potential difference of 3V is maintained between the ends. The emf of the cell, which balances against a length of 100 cm of the potentiometer wire is 0.75 V.

Explanation:

The arrangement of the potentiometer is shown below

When the potentiometer is in balanced condition, Potential difference across A J = Potential difference across AE J

`"V"/"L" xx "l"` = E

∴ emf of cell, E = `3/400 xx 100 = 3/4` = 0.75 V