(a) An iron ring of relative permeability has windings of insulated copper wire of n turns per metre. When the current in the windings is I, find the expression for the magnetic field in the ring.
(b) The susceptibility of a magnetic material is 0·9853. Identify the type of magnetic material. Draw the modification of the field pattern on keeping a piece of this material in a uniform magnetic field.
a) According to Ampere's circuital law, we have
Here it is an iron ring
so field inside the ring is,
where 'r' is the radius of the ring.
Given that number of turns per meter = n
So
Therefore
b)
Given,
susceptibility of a magnetic material = 0.9853
For paramagnetic material the value of susceptibility X is .
Where is a small positive number
Here X is 0.9853 very small number so it is a paramagnetic material.
When paramagnetic material placed in a uniform magnetic field the field gives concentrated lines inside the material.