Question

define soft inductance of a coil write its SI unit ​

Answer 1

Self inductance is defined as the induction of a voltage in a current carrying wire when the current in the wire itself is changing.

Its unit is henry (H)

Answer 2

A current generated in a conductor by a changing magnetic field is proportional to the rate of change of the magnetic field. This effect is called INDUCTANCE and is given the symbol L. It is measured in units called the henry (H) named after the American Physicist Joseph Henry (1797-1878).