$A$ cell of internal resistance $r$ is connected across an external resistance $n r$. Then the ratio of the terminal voltage to the emf of the cell is

$A$ cell of negligible internal resistance and $e.m.f.$ $2 \ V$ is connected to a series combination of $2 \ \Omega$,$3 \ \Omega$,and $5 \ \Omega$ resistors. The potential difference in volts between the terminals of the $3 \ \Omega$ resistor is:

In the given circuit,the potential at the point $B$ with respect to the point $A$ is (in $\text{V}$):

Under what conditions can the current passing through a resistance $R$ be increased by short-circuiting the battery of emf $E_2$? The internal resistances of the two batteries are $r_1$ and $r_2$ respectively.

$A$ battery of internal resistance $4\,\Omega$ is connected to a network of resistors as shown in the figure. If maximum power is to be delivered to the network,the magnitude of $R$ in $\Omega$ should be:

$A$ current of $6\, A$ enters at corner $P$ of an equilateral triangle $PQR$ having $3$ wires of resistance $2 \,\Omega$ each and leaves by the corner $R$. The current $i_{1}$ in ampere is ........ .