List of top Physics Questions on Drift of Electrons and the Origin of Resistivity

The electron drift speed is estimated to be only a few mm/s for currents in the range of a few amperes. How, then, is the current established almost the instant a circuit is closed ?

Consider a cylindrical conductor of length \(l\) and area of cross-section \(A\). Current \(I\) is maintained in the conductor and electrons drift with velocity \(v_d\). Show that the conductivity \(\sigma\) of the material of the conductor is given by \[ \sigma=\frac{ne^2\tau}{m}. \]

Consider a cylindrical conductor of length \(l\) and area of cross-section \(A\). Current \(I\) is maintained in the conductor and electrons drift with velocity \(v_d\). Show that the conductivity \(\sigma\) of the material of the conductor is given by \[ \sigma=\frac{ne^2\tau}{m}. \]

In the (i) absence of electric field, and in the (ii) presence of electric field, the paths of electrons between successive collisions with the positive ions of the metal, are