$A$ circuit is comprised of eight identical batteries and a resistor $R = 0.8\,\Omega$. Each battery has an $emf$ of $1.0\, V$ and internal resistance of $0.2\,\Omega$. The voltage difference across any of the batteries is ............. $V$.

An electric bulb rated as $200 \, W$ at $100 \, V$ is used in a circuit having $200 \, V$ supply. The resistance $R$ that must be put in series with the bulb so that the bulb delivers the same power is $..... \, \Omega$.

The electrochemical equivalents of $Cu$ and $Ag$ are $7 \times 10^{-6}$ and $1.2 \times 10^{-6}$ respectively. If a certain current deposits $14 \ g$ of $Cu$,then the amount of $Ag$ deposited is .......... $g$.

When a resistance of $9 \,\Omega$ is connected across the terminals of a battery,its potential difference decreases from $40 \, V$ to $30 \, V$. The internal resistance of the battery 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

$A$ storage battery of $emf$ $8.0\; V$ and internal resistance $0.5\; \Omega$ is being charged by a $120\; V$ $DC$ supply using a series resistor of $15.5\; \Omega$. What is the terminal voltage of the battery during charging? What is the purpose of having a series resistor in the charging circuit?