Two concentric circular coils X and Y of radii 16 cm and 10 cm, respectively, lie in the same vertical plane containing the north to south direction.
Two concentric circular coils X and Y of radii 16 cm and 10 cm, respectively, lie in the same vertical plane containing the north to south direction. Coil X has 20 turns and carries a current of 16 A, coil Y has 25 turns and carries a current of 18 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.
1 Answers
For coil X Radius of coil, `r_(x)=16 cm =0.16 m` ltbr No. of turns `n_(x)=20`
Current in the coil `I_(x)=16 A` (Anti clockwise) For coil Y
Radius of coil, `r_(y)=10 cm =0.1m`
No. of turns `n_(y)=25`
Current in the coil `I_(y) = 18 A` (clockwise) The magnitude of the magnetic field at the centre of coil X
`B_(x)=(mu_(0))/(4pi).(2I_(x).pi n_(x))/(r_(x))=(10^(-7)xx2xx16xx3.14xx20)/(0.16)T`
`B_(x)=4pi xx10^(-4) T`
The magnitude of magnetic flux at the centre of coil Y
`B_(y)=(mu_(0))/(4pi).(2pi I_(y). n_(y))/(r_(y))=(10^(-7)xx2xxpixx18xx25)/(0.1)=9pi xx10^(-4) T`
Net magnitude field at the centre `B=B_(y)-B_(x)`
`=(9pi - 4pi)xx10^(-4)=5pi xx10^(-4)`
`=1.6xx10^(-3) T` (towards west).