If each resistance in the figure is of $9\,\Omega$,then the reading of the ammeter is ............ $A$.

For the network of resistors shown in the figure,choose the correct option.

$A$ $50\, W$ bulb is in series with a room heater and the combination is connected across the mains. To get maximum heater output,the $50\, W$ bulb should be replaced by a bulb of: (in $, W$)

$A$ copper voltameter and a silver voltameter are connected in parallel. When a total charge $q$ flows through the voltameters,an equal mass of metal is deposited in each. If the electrochemical equivalents of copper and silver are $z_1$ and $z_2$ respectively,then the charge flowing through the silver voltameter is:

Two infinite circuits (shown below) are called 'Circuit $A$' and 'Circuit $B$'. The equivalent resistance of 'Circuit $A$' is $x$ and that of 'Circuit $B$' is $y$ between terminals $1$ and $2$.

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