An air cored coil has a self inductance 0.1 H . A soft iron core of relative permeability 1000 is introduced and the number of turns is reduced $\left(\frac{1}{10}\right)^{\text {th }}$. The value of self inductance is

When the number of turns in a coil are made 3 times without any change in the length of the coil, its self inductance becomes

Two solenoids of equal number of turns have their lengths as well as radii in the same ratio $1: 3$. The ratio of their self inductance will be

If number of turns per unit length in a solenoid is tripled, the self inductance of solenoid will