In the figure given below,the current passing through the $6\,\Omega$ resistor is ........... $A$.

The reading of the ideal voltmeter in the adjoining diagram will be ................. $V$.

Two resistances of $400 \Omega$ and $800 \Omega$ are connected in series with a $6 \text{ V}$ battery of negligible internal resistance. $A$ voltmeter of resistance $10000 \Omega$ is used to measure the potential difference across the $400 \Omega$ resistor. The error in the measurement of potential difference in volts is approximately:

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 resistor of $11 \Omega$ is connected in series with an electric cell,the current flowing in it is $0.5 \ A$. Instead,when a resistor of $5 \Omega$ is connected to the same electric cell in series,the current increases by $0.4 \ A$. The internal resistance of the cell is (in $\Omega$)

When the terminals of a cell are connected by a wire of resistance $4 \Omega$,the potential difference across the cell is $1.6 \text{ V}$. If a wire of the same resistance is connected in parallel with the first,the potential difference becomes $1.33 \text{ V}$. The emf and internal resistance of the cell are respectively