$A$ current $I$ flows through a uniform wire of diameter $d$ when the mean electron drift velocity is $V$. The same current will flow through a wire of diameter $d/2$ made of the same material if the mean drift velocity of the electron 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?

Assertion: Free electrons always keep on moving in a conductor,even then no magnetic force acts on them in a magnetic field unless a current is passed through it.
Reason: The average velocity of free electrons is zero.

Cross-sectional area of a copper wire is equal to the area of a square of length $2 \ mm$. If this copper wire draws $8 \ A$ electric current,then find the drift velocity of free electrons. The number density of electrons in the copper wire is $8 \times 10^{28} \ m^{-3}$.

$A$ current passes through a wire of nonuniform cross-section. Which of the following quantities are independent of the cross-section?

Choose the correct option with respect to the statements $A$ and $B$:
$(A)$: When no electric field is applied across a conductor,the path of free electrons between two successive collisions in it is straight.
$(B)$: When an electric field is applied across a conductor,the drift velocity of electrons is independent of time.