What is Inductance ?

Inductance is the property of an electric circuit to resist the change in current.  A current flowing through a wire has a magnetic field around.  The magnetic flux depends on the current and when the current varies, the magnetic flux varies with it too.  When the magnetic flux varies, an emf is developed across the conductor in accordance with Faraday's law.  

This emf is in the direction opposite to the direction of the current as postulated by Lenz' Law.  The emf induced can be described by the equation below
Inductance Equation

Where V is the voltage, L is the inductance in henry and I is the current.  

The unit of inductance is Henry, named in honour of Joseph Henry who first discovered self-inductance.  The symbol of inductance is L, in honour of Heinrich Lenz who postulated Lenz' Law which describes the direction of the emf induced.