# Formula frustrated?

can someone clever tell the formula ( & explain in layman terms ) the formula for the following calculation

the current in a coil changes from 5a to 2a in 0.05s & induces a voltage of 30v in the coil, what is the inductance of the coil

my brain has ceased

A circuit has an inductance of 1 henry if 1 volt is induced in the circuit when the current changes at the rate of 1 amp per second.

so H=volts/ i2-i1/ t

rate of increase in current = (2-5)/0.005 =-60 amps / sec
inductance = 30v divided by 60a/s= 0.5henerys
inductance of coil = 0.5H
swimmered7 has got it wrong 1 H = Vs divided by Amps per sec
When the current in a coil changes with time, an emf is induced in the coil according to Faraday's law. The self-induced emf is:

E = -L (dI/dt) where L is the inductance of the coil.

So, as helpful as the above sentence is, the SI unit of inductance is henry (H), which equals 1 volt-second per ampere.

1 H = 1 (Vs/A)

You have A= 5 - 2 = 3 and Vs= (30)(0.05)= 15

Therefore, H= 15/3=5

The inductance of your coil is 5 H.

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