Question

The relative permeability of a medium is 0.075. What is the magnetic susceptibility?
(A) 0.925
(B) -0.925
(C) 1.075
(D) -1.075

Answer 1

Hint: The relative permeability is directly related to the magnetic susceptibility by the formula ${\mu _r} = (1 + {\chi _m})$. Substitute the data to know the value of magnetic susceptibility of that medium.

Complete step – by- step solution:
Relative permeability is the ratio of magnetic permeability to absolute permeability of air or vacuum. It is denoted by μr.
Magnetic susceptibility is the property of the substance which shows how easily a substance can be magnetised. It is denoted by ${\chi _m}$. It is a scalar quantity with no units and dimensions.
These both are related by the following expression
${\mu _r} = (1 + {\chi _m})$
From the question we know the value of relative permeability of the medium.
\[{\mu _r} = {\text{ }}0.075\]
Now, we can put this value into the expression to get the value of magnetic susceptibility of the medium.
$
  {\chi _m} = {\mu _r} - 1 \\
  {\chi _m} = 0.075 - 1 \\
  {\chi _m} = - 0.925 \\
  $
Hence, the magnetic susceptibility is equal to -0.925 and the correct option above is B.

Note: Magnetic susceptibility is defined as the ratio of intensity of magnetization (I) to the magnetic intensity (H) applied to the substance.