Question

A long insulated wire is stretched along the x-axis. A current of 2.0 A flows in this wire in the positive x-direction.

Another long insulated wire is stretched along the y-axis. It carries a current of 9.3 A in the negative y-direction.

What is the magnitude of the magnetic field at the point (x=6.9cm, y=1.8cm)? The answer may be given in the units of mT or uT.

The answer should be positive if the direction of the magnetic field is up (in the positive z-direction), and negative if the direction of the magnetic field is down.

Answer 1

0 =4x10^-7 T.m/A

B = oi/2d

i =2 A, x =6.9 cm

B 1= (4x10^-7*2)/(2*0.069)

B1 = 57.97x10^-7 T

Current is along +x direction. According to Amphere's law B is along downward direction (-z)

i =9.3 A, x =1.8 cm

B2= (4x10^-7*9.3)/(2*0.018)

B2 = 1033.3x10^-7 T

Current is along - y direction. According to Amphere's law B is along downward direction (-z)

B =B1+B2

B = (57.97x10^-7 )+ (1033.3x10^-7)

B =1091.27x10^-7T

B = 1.091x10^-4 T along down ward direction

B = - 1.091x10^-4 T