$A$ bulb rated at $(100\,W, 200\,V)$ is used on a $100\,V$ line. The current in the bulb is

In the circuit shown below,the cell has an $e.m.f.$ of $10\,V$ and internal resistance of $1\,\Omega$. The other resistances are shown in the figure. The potential difference ${V_A} - {V_B}$ is ................ $V$.

$A$ galvanometer of resistance $G$ is connected in a circuit. Now,a resistance $R$ is connected in series with the galvanometer. To keep the main current in the circuit unchanged,the resistance $S$ to be put in parallel with the series combination of $G$ and $R$ is:

In the given figure,the equivalent resistance between the points $A$ and $B$ is ............ $\Omega$.

In the circuit shown,$n$-identical resistors $R$ are connected in parallel $(n > 1)$ and the combination is connected in series to another resistor $R_0$. In the adjoining circuit,$n$ resistors of resistance $R$ are all connected in series along with $R_0$. The batteries in both circuits are identical and the net power dissipated in the $n$ resistors in both circuits is the same. The ratio $R_0 / R$ is

The e.m.f. of a cell is $E \text{ volts}$ and its internal resistance is $r \text{ ohm}$. The resistance in the external circuit is also $r \text{ ohm}$. The potential difference across the cell will be