Assertion : The ability of a material to permit the passage of magnetic lines of force through it is called magnetic permeability.
Reason: For a perfect diamagnetic substance, permeability is always one.

Options

A. If both assertion and reason are true and reason is the correct explanation of assertion.
B. If both assertion and reason are true and reason is not the correct explanation of assertion.
C. If assertion is ture but reason is false.
D. If both assertion and reason are false.

Answer

C

Explanation

For a perfectly diamagnetic substance,
`B=mu_(0)(H+I ) =0 thereforeI =- H`.
Therefore,
`chi_(m)=(1)/(H)=- 1`
Therefore relative permeability
`mu_(r)=1+chi_(m)= 1- 1= 0. thereforemu=mu_(0)mu_(r) = "zero"`
i.e. for a perfectn diamagnetic material permeability is zero.