Question

2.Find the magnetic induction in the surface of a spherical superconductor of
radius R, which experiences a uniform magnetic field B.​

Answer 1

Answer:

B=B0−(3R^3)(B0.r)r/2r^5+B0(R^3/2r^3)

Explanation:

Inside the shell the net magnetic field is 0, and at the surface also. The magnetic field of a magnetic diople of moment m is

Bm=μ0/4π[3(m.r)r/r5−m/r3]

The boundary condition at the surface which is at an angle θ with the vertical is B0,^n+Bm,^n=0

So,B0cosθ+μ0/4π(2mcosθ/R3)=0

Therefore at m=−(2π/μ0)R3B0,

the boundary condition are satisfied on the surface of the shell.Hence, B=B0−(3R^3)(B0.r)r/2r^5+B0(R^3/2r^3)