$A$ potential difference of $5 \,V$ is applied across a conductor of length $10 \,cm$. If the drift velocity of electrons is $2.5 \times 10^{-4} \,m/s$,then the electron mobility will be ............ $m^2 V^{-1} s^{-1}$.

Derive the relation between electric current and drift velocity.

$A$ constant electric current $I$ is passed through a straight conductor of length $l$. If $S$ is the specific charge of an electron,then the total momentum of the electrons is:

$A$ charged particle is moving in an electric field of $3 \times 10^{-10} \text{ Vm}^{-1}$ with mobility $2.5 \times 10^6 \text{ m}^2 \text{V}^{-1} \text{s}^{-1}$. Its drift velocity is:

$A$ straight conductor of uniform area of cross-section carries a current $I$. If $s$ is the specific charge (charge-to-mass ratio) of the electron,what is the total momentum of all the electrons per unit length of the conductor due to their drift velocity?

The relaxation time $\tau$ is nearly independent of the applied $E$ field,whereas it changes significantly with temperature $T$. The first fact is (in part) responsible for Ohm's law,whereas the second fact leads to the variation of resistivity $\rho$ with temperature. Elaborate why?