magnitude of magnetic field

Question

A circular region of r=0.003 m has a uniform displacement current that flow perpendicular to the plane with Ip = 0.500 A.  What is the magnitude of the magnetic field due to the displacement current at a radial displacement of r=0.002 m and r = 0.005m?

Answer 1

Hi Mavis

For r= 0.005 m the entire current is threading through the loop 

so 

B2 =  μ_{0 I}  /( 2pi R)

        4 pi * 10 ^-7 / 2pi R  = 2* 10^-7/ R  where R = 0.005 m

B2 = 2* 10-7/ 0.005 

= 4*10^-5 Tesla

 

For B1 at a distance  r₁ = .002 m , we have to take only that fraction of current which threads through area pi r_1²

 

Where r₁ = 0.002 m