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

The magnitude and direction of the current in the circuit shown will be

$A$ battery has an $e.m.f.$ of $4 \ V$ and an internal resistance of $r$. When the battery is connected to an external resistance of $2 \ \Omega$,a current of $1 \ A$ flows through the circuit. If the terminals of the battery are short-circuited (connected directly),what will be the current in $A$ flowing through it?

$A$ 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 ............. $\Omega$.

When connected across the terminals of a cell,a voltmeter measures $5\,V$ and a connected ammeter measures $10\,A$ of current. $A$ resistance of $2\,\Omega$ is connected across the terminals of the cell. The current flowing through this resistance will be ............ $A$.

In the given circuit,if the measuring instruments are ideal,then the reading of ammeter $A_1$ is: