Though the electron drift velocity is small and electron charge is very small, a conductor can carry an appreciably large current because

$\mathrm{I} - \mathrm{V}$ graphs for two different electrical appliances $P$ and $Q$ are shown in the diagram. If ${\mathrm{R}}_{\mathrm{P}}$ and $R_{\mathrm{Q}}$ be the resistances of the devices, then

In the given circuit, the current through $2 \mathrm{\Omega }$ resistor is

The effective resistance between $P$ and $Q$ for the following network is

Five identical resistors each of resistance $R=1500 \Omega$ are connected to a $300 \mathrm{V}$ battery as shown in the circuit. The reading of the ideal ammeter $A$ is