$A$ battery having $e.m.f.$ $5\,V$ and internal resistance $0.5\,\Omega$ is connected with a resistance of $4.5\,\Omega$. The voltage at the terminals of the battery is ............. $V$.

Find the current through the $2\, \Omega$ resistance. (in $, A$)

For the given circuit,if $i = 0.25 \, A$,what is the value of $R$ in $\Omega$?

$B_{1}$, $B_{2}$ and $B_{3}$ are three identical bulbs connected to a battery of steady $EMF$ with key $K$ closed. What happens to the brightness of the bulbs $B_{1}$ and $B_{2}$ when the key $K$ is opened?

The equivalent resistance and potential difference between $A$ and $B$ for the circuit shown are respectively:

The internal resistance of a $2.1\, V$ cell which gives a current of $0.2\, A$ through a resistance of $10\,\Omega$ is ............. $\Omega$.