If a rate of change of current of 4 `As^(-1)` induces an emf of 20 mV in a solenoid, the self inductance of the solenoid is

If a rate change of current of 4As^(-1) induces an emf of 20mV in a solenoid, what is the self inductance of the solenoid?

If a rate of change of current of 2 A.s^(-1) induces an emf of 10 mV in a solenoid, what is the self-inductance of the solenoid?

If a rate of change of current of 4 A s^-1 induces an e.m.f. of 20 mV in a solenoid, what is the self-inductance of the solenoid?

If the rate of change of current 2As^-1 induces an e.m.f. of 40mV in a solenoid, what is the self inductance of this solenoid?

If the rate of change of current 2A second induces an emf of 40 mV in the solenoid, what is the self-inductance of this solenoid?

Self induction of a solenoid is