When a long straight uniform rod is connected across an ideal cell, the drift velocity of electrons in it is $v$. If a uniform hole is made along the axis of the rod and the same battery is used, then the drift velocity of electrons becomes

Statement $(I)$: Specific resistance depends on the nature of the material and is independent of the temperature of the material.
Statement $(II)$: $A$ wire of resistance $6 \ \Omega$ is drawn out so that its new length is four times its original length. The resistance of the new wire is $48 \ \Omega$.
Statement $(III)$: Drift velocity is the average constant velocity acquired by free electrons inside a metal by the application of an electric field,which results in current.
Which of the following is correct?

Which of the following is a vector quantity?

Drift velocity $V_d$ varies with the intensity of electric field $E$ as per the relation:

The potential difference across a conducting wire of length $20 \ cm$ is $30 \ V$. If the electron mobility is $2 \times 10^{-6} \ m^2 \ V^{-1} \ s^{-1}$,then the drift velocity of the electrons is

Every atom contributes one free electron in copper. If $1.1 \ A$ current is flowing in a copper wire having a $1 \ mm$ diameter,then the drift velocity (approx.) will be (Density of copper $= 9 \times 10^3 \ kg \ m^{-3}$ and atomic weight $= 63$).