Correct Answer - Option 4 : bound electrons or ion oscillation and dipole relaxation
Complex permeability: It is the complex quotient of the magnetic flux density and magnetic field strength in a material when one of these quantities varies sinusoidally with time and that component of the other is chosen which varies sinusoidally with time at the same frequency, that is, the fundamental component.
The vectors representing the flux density and field strength are assumed to be collinear:
µ = μ' − j μ''
where µ' and µ" are the real and imaginary components respectively of the complex permeability
Two important mechanisms that give rise to a complex permeability and thus resulting wave losses are bound electrons or ion oscillation and dipole relaxation.
