$A$ cell sends a current of $0.9\, A$ through a resistance of $2\, \Omega$ and a current of $0.3\, A$ through a resistance of $7\, \Omega$. The internal resistance of the cell is ............. $\Omega$.

$A$ voltmeter of resistance $998\ \Omega$ is connected to a cell of $emf$ $2\ V$ and internal resistance $2\ \Omega$. The error in the measurement of $emf$ will be:

Inside a superconducting ring,six identical resistors each of resistance $R$ are connected as shown in the figure. Imagine a battery of $emf$ $E$ connected between points $O$ and $1$,with its positive terminal connected to $O$.

If the ammeter in the given figure shows a reading of $2 \, A$,find the value of $R$ in $\Omega$.

$A$ voltameter has a resistance of $2\,\Omega$. It is connected in series with a $10\,V$ battery and a $3\,\Omega$ resistor. The mass deposited at the cathode in a certain time is $1\,g$. Now,the voltameter and the $3\,\Omega$ resistor are connected in parallel with the battery. The increase in the mass of the metal deposited in the same time will be $...\,g$.

The equivalent resistance of the infinite network given below is: