ADDITIONAL EXERCISES

. Two concentric circular coils X and Y of radii cm and cm, respectively, lie in the same vertical plane containing the north to south direction. Coil X has turns and carries a current of A; coil Y has turns and carries a current of A. The sense of the current in X is anticlockwise, and clockwise in Y, for an observer looking at the coils facing west.

Give the magnitude and direction of the net magnetic field due to the coils at their centre. . A magnetic field of G ( G = – T) is required which is uniform in a region of linear dimension about cm and area of cross-section about – m2. The maximum current-carrying capacity of a given coil of wire is A and the number of turns per unit length that can be wound round a core is at most turns m– .

Suggest some appropriate design particulars of a solenoid for the required purpose. Assume the core is not ferromagnetic. . For a circular coil of radius R and N turns carrying current I, the magnitude of the magnetic field at a point on its axis at a distance x from its centre is given by, ( /