The $SI$ unit of the current density is . . . . . . .

In a wire with a cross-sectional area of $1 \, cm^2$ carrying a current of $24 \, mA$,the electron number density is $3 \times 10^{23} \, m^{-3}$. What is the drift velocity?

There are $0.8 \times 10^{23}$ free electrons $/ cm^3$ in copper. If a $0.2 \, A$ current is flowing in a copper wire, then the drift velocity of electrons will be, given the cross-sectional area of the wire is $0.01 \, cm^2$.

$A$ current of $1.344 \, A$ flows through a copper wire of cross-sectional area $1 \, mm^2$. If the number of free electrons per unit volume is $8.4 \times 10^{22} \, cm^{-3}$,then the drift velocity is:

The drift speed of electrons in a material is found to be $0.3 \ m s^{-1}$ when an electric field of $2 \ V m^{-1}$ is applied across it. The electron mobility (in $m^2 \ V^{-1} \ s^{-1}$) in the material is

The potential difference between the ends of a straight conductor of length $20 \ cm$ is $16 \ V$. If the drift speed of the electrons is $2.4 \times 10^{-4} \ ms^{-1}$,the electron mobility in $m^2 \ V^{-1} \ s^{-1}$ is