How does self inductance of a solenoid change when number of turns is double keeping othe parameters same ?

How does self inductance of a coil depend on number of turns in the coil?

How does the self inductance of an air coil change, when the number of turns in the coil is decreased?

What will happen to the inductance of a solenoid a. when the number of turns and the length are double keeping the area of cross section same? b. when the air inside the solenoid is replaced by iron of relative permeability mu_(r) ?

What will happen to the inductance of a solenoid a. when the number of turns and the length are double keeping the area of cross section same? b. when the air inside the solenoid is replaced by iron of relative permeability mu_(r) ?

The self inductance L of a solenoid depends on the number of turns per unit length 'n' as

How does the self inductance of a coil change if the number of turns in it is reduced from 600 to 500?