Question

what is this and what is permeability.....​

Answer 1

Answer:

In electromagnetism, permeability is the measure of the resistance of a material against the formation of a magnetic field, otherwise known as distributed inductance in transmission line theory. Hence, it is the degree of magnetization that a material obtains in response to an applied magnetic field.

this is for permeability

this is for permeability& u have written it's not understandable please write it clearly as by looking it looks like a formula in which I1 & I2 are the current & d is diameter.

hope I had helped you a bit.