In the following circuit resistance of the potentiometer, the wire is $100 \mathrm{\Omega }$. Power consumption in potentiometer wire is the same when a jockey is placed at $10 \mathrm{cm}$ from end $A$ or end $B$. The internal resistance of the cell $\left(r\right)$ is

In the circuit shown, the reading of the ammeter is doubled after the switch is closed. Each resistor has the resistance $R=1 \mathrm{\Omega }$ and the ideal cell has an emf $\epsilon$ of $10 \mathrm{V}$. Then, the ammeter

When an ammeter of negligible internal resistance is inserted in series with circuit it reads $1 \mathrm{A}$. When the voltmeter of very large resistance is connected across $X$ it reads $1 \mathrm{V}$. When the point $A$ and $B$ are shorted by a conducting wire, the voltmeter measures $10 \mathrm{V}$. The internal resistance of the battery $\left(r\right)$ is equal to

Four wires of equal length $2 \mathrm{m}$ are arranged as shown in the figure. Wires, $2, 3$ and $4$ are of equal cross-sectional area and wire $1$ is of half the cross-section of these wires. By how much distance pointer at point $5$ must be moved to get the null point?

In the circuit shown in the figure, the reading of the voltmeter is $V_1$ when only $S_1$ is closed, reading of voltmeter is $V_2$ when only $S_2$ is closed, and reading of voltmeter is $V_3$ when both $S_1$ and $S_2$ are closed. Then

Find the reading of the ideal ammeter connected in the given circuit. Assume that the cells have negligible internal resistance.