When current flows through a conductor,the order of magnitude of the drift velocity of electrons is

In a wire of circular cross-section with radius $r$,free electrons travel with a drift velocity $V$ when a current $I$ flows through the wire. What is the current in another wire of half the radius and of the same material when the drift velocity is $2V$?

$A$ 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 electric field $E$,current density $J$ and conductivity $\sigma$ of a conductor are related as

The drift velocity of electrons in a silver wire with a cross-sectional area of $3.14 \times 10^{-6} \, m^2$ carrying a current of $20 \, A$ is. Given the atomic weight of $Ag = 108$ and the density of silver $= 10.5 \times 10^3 \, kg/m^3$,the drift velocity is $.......... \times 10^{-4} \, m/s$.

$A$ silicon block at $300\,K$ has a length of $10\,cm$ and a cross-sectional area of $1 \times 10^{-4}\,m^2$. If a $2\,V$ battery is connected across its ends parallel to the length,find the current flowing through it. The electron mobility is $0.14\,m^2V^{-1}s^{-1}$ and the electron number density is $1.5 \times 10^{16}\,m^{-3}$.