There is a current of $40 \ A$ in a wire of cross-sectional area $10^{-6} \ m^2$. If the number of free electrons per $m^3$ is $10^{29}$,then the drift velocity will be:

Suppose a current-carrying wire has a cross-sectional area that gradually becomes smaller along the wire,having the shape of a very long cone as shown in the figure. Choose the correct statement.

If the ratio of the radii of two wires of the same material is $1 : 2$ and the ratio of the current flowing through them is $4 : 1$,what is the ratio of their drift velocities?

The number density of free electrons in a copper conductor is $8.5 \times 10^{28} \; m^{-3}$. How long does an electron take to drift from one end of a wire $3.0 \; m$ long to its other end? The area of cross-section of the wire is $2.0 \times 10^{-6} \; m^2$ and it is carrying a current of $3.0 \; A$.

The electric intensity $E$,current density $j$,and specific resistance $\rho$ (often denoted as $k$ in some texts) are related to each other by the relation:

For which of the following dependencies of drift velocity $v_d$ on electric field $E$ is Ohm's law obeyed?