In the given circuit,the reading of the ammeter is ................. $A$ (assume internal resistance of the battery is zero).

$A$ 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:

In the circuit shown,the cells $A$ and $B$ have negligible resistance. For $V_{A} = 12 \; V$,$R_{1} = 500 \; \Omega$ and $R = 100 \; \Omega$,the galvanometer $(G)$ shows no deflection. The value of $V_{B}$ is .... $V$.

For the previous objective,which of the following graphs is correct?

Three voltmeters,all having different internal resistances,are connected as shown in the figure. When a potential difference is applied across $A$ and $B$,their readings are $V_1, V_2$,and $V_3$. Choose the correct option.

Current flowing through the cell and potential difference between its two poles obtained by observations are given in the table below. The internal resistance of the cell is $r$.

Order	$V \ (V)$	$I \ (A)$
$1$	$1.0$	$0.08$
$2$	$0.5$	$0.18$
$3$	$0.8$	$0.12$

Find the $emf$ $(\varepsilon)$ of the cell used in the experiment. (in $V$)