The Total solution for NCERT class 6-12
Two concentric circular coils Xand Y of radii 16 cm and 10 cm, respectively, lie in the same vertical planecontaining the north to south direction. Coil X has 20 turns and carries acurrent of 16 A; coil Y has 25 turns and carries a current of 18 A. The senseof the current in X is anticlockwise, and clockwise in Y, for an observerlooking at the coils facing west. Give the magnitude and direction of the netmagnetic field due to the coils at their centre.
Radius of coil X, r1 =16 cm = 0.16 m
Radius of coil Y, r2 =10 cm = 0.1 m
Number of turns of on coilX, n1 = 20
Number of turns of on coilY, n2 = 25
Current in coil X, I1 =16 A
Current in coil Y, I2 =18 A
Magnetic field due to coil X attheir centre is given by the relation,
Where,
= Permeability of freespace =
Magnetic field due to coil Y attheir centre is given by the relation,
Hence, net magnetic field can beobtained as: