A potentiometer is used for the determination of internal resistance of a $1.6\mathrm{ }\mathrm{V}$ cell. The balance point of the cell in open circuit is$\mathrm{ }75.8\mathrm{ }\mathrm{c}\mathrm{m}$. When a resistor of $10.2 \mathrm{\Omega }$ is used in the external circuit of the balance point shifts to $68.3\mathrm{ }\mathrm{c}\mathrm{m}$ length of the potentiometer wire. The internal resistance of the cell is

The figure shows a simple potentiometer circuit for measuring a small emf produced by a thermocouple. The meter wire $PQ$ has a resistance $5 \mathrm{\Omega }$ and the driver cell has an emf of $2 \mathrm{V}$. If a balanced point is obtained $0.600 \mathrm{m}$ along $PQ$ when measuring an emf of $6.00 \mathrm{mV},$ what is the value of resistance $R$?

In a potentiometer experiment, a standard cell of emf $1.1 \mathrm{V}$ is balanced at $2.20 \mathrm{m}$ length. Potential difference across a resistance wire is balanced at $95 \mathrm{cm}$ length and voltmeter read this potential difference as $0.5 \mathrm{V}$. Then, error in the voltmeter will be,