In a coil,current falls from $5\, A$ to $0\, A$ in $0.2\, s$. If an average $emf$ of $150\, V$ is induced,then the self-inductance of the coil is.....$H$

The self-inductance of a coil depends on

In a circular conducting coil,when current increases from $2 \,A$ to $18 \,A$ in $0.05 \,s$,the induced $e.m.f.$ is $20 \,V$. The self-inductance of the coil is.....$mH$.

The coefficient of self-inductance of a solenoid is $0.18\, mH$. If a core of soft iron of relative permeability $900$ is inserted,then the coefficient of self-inductance will become nearly.....$mH$.

In a circular coil,when the number of turns is doubled and the resistance becomes $1/4$th of the initial value,then the inductance becomes ....... times.

The current in a coil of self-inductance $2.0 \, H$ is increasing according to $I = 2 \sin(t^2) \, A$. The amount of energy spent during the period when current changes from $0$ to $2 \, A$ is ...... $J$.