If the flux produced by one coil does not link the other coil, then the value of the coefficient of coupling will be __________.

The correct answer is option  4):(zero)

Concept:

• The fraction of magnetic flux produced by the current in one coil that links with the other coil is called the coefficient of coupling between the two coils. It is denoted by (k)
• The coefficient of coupling is a factor used when two coils are mutually coupled in a magnetic circuit.
• The coupling coefficient K is a measure of the magnetic coupling between two coils.
• The coupling coefficient is the amount of inductive coupling that exists between the two coils is expressed as a fractional number between 0 and 1.
• The coupling factor between the coils or the coupling coefficient is given as
• k=1, when the flux produced by one coil, completely links with the other coil and is called magnetically tightly coupled.
• k=0, when the flux produced by one coil, does not link at all with the other coil and thus the coils are said to be magnetically isolated.

0 ≤ K ≤ 1

K < 0.5 loosely coupled

K > 0.5 tightly coupled

\(K = \frac{M}{{\sqrt {{L_1}{L_2}} }}\)

\(K \propto \frac{1}{{\sqrt {{L_1}{L_2}} }}\)

Where M = Mutual inductance L₁ and L₂ = Self-inductance