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

$A$ silver wire of length $3 \,m$ and of cross-sectional area $6.14 \times 10^{-6} \,m^2$ carries a current of $6 \,A$. The atomic weight and density of silver are $108 \,g/mol$ and $10500 \,kg/m^3$,respectively. $A$ silver atom contributes one free electron for conduction. The Avogadro number is $6.023 \times 10^{23} /mol$. The drift velocity of electrons in silver is close to:

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

The current density in a cylindrical wire of radius $4 \; mm$ is $4 \times 10^{6} \; A \cdot m^{-2}$. The current through the outer portion of the wire between radial distance $\frac{R}{2}$ and $R$ is $\dots \; \pi \; A$.

When a potential difference is applied across the ends of a linear metallic conductor,

Current density in a cylindrical wire of radius $R$ varies with radial distance as $J(r) = \beta(r + r_0)^2$. The current through the shaded section of the wire shown in the figure is: