The current in the primary circuit of a potentiometer is $0.2 \, A$. The specific resistance and cross-section of the potentiometer wire are $4 \times 10^{-7} \, \Omega \cdot m$ and $8 \times 10^{-7} \, m^2$ respectively. The potential gradient will be equal to .............. $V/m$.

In a potentiometer wire experiment, the $emf$ of a battery in the primary circuit is $20\,V$ and its internal resistance is $5\,\Omega$. There is a resistance box in series with the battery and the potentiometer wire, whose resistance can be varied from $120\,\Omega$ to $170\,\Omega$. The resistance of the potentiometer wire is $75\,\Omega$. Which of the following potential differences can be measured using this potentiometer?

$A$ $2\,V$ battery,a $15\,\Omega$ resistor,and a potentiometer of $100\,cm$ length are all connected in series. If the resistance of the potentiometer wire is $5\,\Omega$,then the potential gradient of the potentiometer wire is ............... $V/cm$.

$A$ cell in a secondary circuit gives a null deflection for $2.5 \ m$ length of a potentiometer wire having a total length of $10 \ m$. If the length of the potentiometer wire is increased by $1 \ m$ without changing the cell in the primary circuit,the new position of the null point is: (in $m$)

The potentiometer wire $AB$ is $600 \, cm$ long. At what distance from $A$ should the jockey $J$ touch the wire to get zero deflection in the galvanometer?

Potentiometer measures the potential difference more accurately than a voltmeter because