$A$ silver and zinc voltameter are connected in series and a current $i$ is passed through them for a time $t$ liberating $W \, g$ of zinc. The weight of silver deposited is nearly ..............$W$.

Two current elements $P$ and $Q$ have current-voltage characteristics as shown below. Which of the graphs given below best represents the current-voltage characteristics when $P$ and $Q$ are in series?

When an electric heater is switched on, the current flowing through it $(I)$ is plotted against time $(t)$. Taking into account the variation of resistance with temperature, which of the following best represents the resulting curve?

$A$ cell having an emf $\varepsilon$ and internal resistance $r$ is connected across a variable external resistance $R$. As the resistance $R$ is increased,the plot of potential difference $V$ across $R$ is given by:

If the resistance of a heating coil is $484\, \Omega$ and the supply voltage is $220\, V\ AC$,how much time in $sec$ will the heater take to raise the temperature of $100\, g$ of water by $50^\circ C$?

Column-$I$ gives certain physical quantities associated with the flow of current through a metallic conductor. Column-$II$ gives some mathematical relations involving electrical quantities. Match Column-$I$ and Column-$II$ with appropriate relations.

$A$. Mobility	$P$. $\frac{m}{ne^2 \rho}$
$B$. Electrical conductivity	$Q$. $neAv_{d}$
$C$. Relaxation period	$R$. $\frac{v_{d}}{E}$
$D$. Current	$S$. $\frac{J}{E}$