Question

The most exotic diamagnetic materials are superconductors. They exhibit perfect diamagnetism and perfect conductivity. The values of magnetic susceptibility \((\chi)\) and relative permeability \((\mu_r)\) for such materials are:

• A. \(\chi = 1,\; \mu_r = 0\)
• B. \(\chi = -1,\; \mu_r = 0\)
• C. \(\chi = 0,\; \mu_r = 1\)
• D. \(\chi = -1,\; \mu_r = 1\)

Hint:

For superconductors: \[ \boxed{\chi=-1} \] \[ \boxed{\mu_r=0} \] because \[ \mu_r = 1+\chi \] The complete expulsion of magnetic field from a superconductor is called the \[ \boxed{\text{Meissner Effect}} \] which is a favorite CUET/JEE conceptual question.

Answer 1

The Correct Option is B

Step 1: Recall the magnetic properties of superconductors. A superconductor exhibits: \[ \boxed{\text{Perfect diamagnetism}} \] This phenomenon is known as the \[ \boxed{\text{Meissner Effect}} \] in which magnetic flux is completely expelled from the interior of the material.

Step 2: Find the magnetic susceptibility. For a perfect diamagnetic substance, \[ \chi=-1 \]

Step 3: Use the relation between permeability and susceptibility. The relative permeability is related to susceptibility by \[ \mu_r = 1+\chi \] Substituting \[ \chi=-1 \] gives \[ \mu_r = 1-1 \] \[ \mu_r = 0 \]

Step 4: Identify the correct option. Thus, \[ \boxed{\chi=-1,\qquad \mu_r=0} \] Hence, the correct answer is: \[ \boxed{\text{(B)}} \]