The current density in a cylindrical wire of radius 4 mm is `4xx 10^6 Am^(-2)`. The current through the outer portion of the wire between radial distances `R/2` and R is ______ `pi` A

The current density varies radical distance r as J=ar^(2) , in a cylindrical wire of radius R. The current passing through the wire between radical distance R//3 and R//2 is,

A cylindrical wire if radius R = 2 mm is of uniform area of cross-section. The current density through a cross-section varies with radial distance r as J = ar^(2) , where a =3.2 xx 10^(11)A//m^(2) and r is in metres. What is the current through the outer portion of the wire between radial distances R//2 and R?

The current density bar(J) inside a long, solid cylindrical wire of radius a = 12 mm is in the direction of the central axis, and its magnitude varies linearly with radial distance r from the axis according to J = (J_(0) r)/(a) , where J_(0) = (10^(5))/(4 pi) A//m^(2) . Find the magnitude of the magnetic field at r = (a)/(2) in mu T

A current of 2 amp. flows in a long, straight wire of radius 2 mm . The intensity of magnetic field on the axis of the wire is

Current flows through a constricted conductor as shown in figure The radius and the current density to the left of constriction are 2 mm and 4.2xx10^(5)Am^(-2) . (a) How much current flows through the constriction? (b) If the current density is doubled as emerges from the right side of the constriction, what is the radius r_(2) ?

A current of 4.8 A is flowing in a copper wire of cross-sectional area 3xx10^(-4) m^(2) . Find the current density in the wire.

A uniform current I is flowing in a long wire of radius R . If the current is uniformly distributed across the cross-sectional area of the wire, then