Question

Why does inductance increase with the iron core?

Answer 1

Inductance:

It is the tendency of an electrical conductor to oppose the change in electric current flowing through it.

Equation for inductance is given by,

$L=\frac{N^2{\mu }_{r}A}{l}$

Where,

$L$ is the inductance, ${\mu }_r$ is the relative permeability, $N$ is the number of turns, $A$ is the area of the coil, and $l$ is the length of the coil.

Explanation:

1. In these two cases shown in the figure, all other factors are equal except the relative permeability. In case of iron core, relative permeability will be more and hence the inductance will be high according to the equation.
2. Iron core has high magnetic permeability. A material with high magnetic permeability will have high magnetic flux for a given magnetic field force.
3. The greater the permeability of the material used greater the inductance.

So, inductance increase with iron core since inductance and relative permeability are directly proportional in this case.