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

Answer

D

Explanation

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