A large Number N of closely spaced turns of find wire are wound in a single layer upon The surface of wooden sphere of radius 'R' with the planes of the turns perpendicular to the axis of the sphere and completely covering it's surface. The magnetic fleld intensity at the centre of the sphere is `alpha times(mu_(0)NI)/(8R)` determine the value of `alpha`?

A thin wire is wound very tightly in one layer on the surface of a sphere of paramagnetic material (mu_(r)~~1) . The planes of all the turns can be assumed to be perpendicular to the same diameter of the sphere. The turns over the entire surface of the sphere. The radius of the sphere is R , the total number of turns is N , and the current in the winding is I . Find the magnetic induction at the centre of the sphere. (Given mu_(0)NI=20R )

In Fig. a coil of single turn is wound on a sphere of radius r and mass m. The plane of the coil is parallel to the inclined plane and lies in the equatorial plane of the sphere. If the sphere is in rotational equilibrium, the value of B is [Current in the coil is i]

A sphere of radius R, uniformly charged with the surface charge density sigma rotates around the axis passing through its centre at an angular velocity. (a) Find the magnetic induction at the centre of the rotating sphere. (b) Also, find its magnetic moment.

A charger Q is distributed uniformly on a ring of radius of r. A sphere of equal radius r is constructed with its centre a t the periphery of the ring. The flux of the electric field through the surface of the sphere is (Q)/(n epsilon_(0)) , The value of n is

A tightly- wound, long solenoid is kept with its axis parallel to a large metal sheet carrying a surface current. The surgace current through a width dl of the sheet is Kdl and the number of turns per unit length of the solenoid is n. The magnetic field near the centre of the solenoid is found to be zero. (a) find the current in the solenoid. (b) If the solenoid is rotated to make its axis perpendicular to the metal sheet, what would be the magnitude of the magnetic field near its centre?

A tightly wound solenoid of radius 'a' and length 'l' has n turns per unit length. It carries an electric current i. Magnetic field at a distance (l)/(4) from one of the end (inside the solenoid on its axis) is B=(mu_(0)ni(sqrt5+3))/(sqrtK) for l=4a . Then find the value of K.

A tightly wound solenoid of radius 'a' and length 'l' has n turns per unit length. It carries an electric current i. Magnetic field at a distance (l)/(4) from one of the end (inside the solenoid on its axis) is B=(mu_(0)ni(sqrt5+3))/(sqrtK) for l=4a . Then find the value of K.

A long straight copper wire, of circular cross ection, contains n conduction electrons per unit volume, each of charge q. Show that the current l in the wire is given by l = nqv pi a^(2) where v is the drift velocity and a is the radius of the wire. At a radial distance r from the axis of the wire, what is the direction of the magnetic field B due to the current l? Assuming that the magnitude of the field is B = mu_(0)l//2pir(r ge a) , obtain an expression for the Lorentz force F on an electron moving with the drift velocity at the surface of the wire. If l = 10 A and a = 0.5mm, calcualte the magnitude of (a) the drift velocity and (b) the forcce, given that for copper, n = 8.5 xx 10^(28) m^(-3)

A sphere of radius R has a variable charge density rho(r)=rho_(0)r^(n-1)(rleR) . If ratio of "potential at centre" and "potential at surface" be 3//2 then find the value of n

A small sphere of radius R is held against the inner surface of a larger sphere of radius 6R. The mass of large and small spheres are 4M and M respectively. This arrangement is placed on a horizontal table. There is no friction between any surface of contact. The small sphere is now released. The x coordinate of the centre of the larger sphere when the smaller sphere reaches the other extreme position, is found to be (L + nR) , find n.