(a) When the current in a coil changes from `8A` to `2A` in `3xx10^(-2)s` , the emf induced in the coil is `2V` . The self-induced of coil in `mH`
(b) A `12V` battery conneted to a `6Omega` . `10H` coil through a switch drives a constant current in the circuit. The switch is suddenly opened. Assuming that it took 1msec to open the switch, calculate the average emf induced across the coil.
(c) The equivalent inductance of two inductored in series. What is the value of inductances of the individual inductors?
(d) If `i=5A` and decreasing at a rate of `10^(3)` (A/sec), find `V_(B)-B_(A)` .

Explanation

`bar(e)=-L(Deltai)/(Deltai)`
`=-L((i_(2)-i_(1)))/(Deltat)`
`2=-L((2-8))/(3xx10^(-2))`
`L=10^(-2)H=10xx10^(-3)H=10mH`
(b) In steady state
`i_(1)(12)/(6)=2A`
When switch is opened
`i_(2)=0`
`Deltat=1m//sec=10^(-3)sec`
`bar(e)=-L(Deltai)/(Deltat)=-L(i_(2)-i_(1))/(Deltat)`
`=-10((0-2))/(10^(-3))=2xx10^(4)V`
(c) `(L_(1)L_(2))/(L_(1)+L_(1))=2.4`
`L_(1)+L_(2)=10`
`L_(1)L_(2)=24`
Solving, `L_(1)=6H` , `L_(2)=4H`
`i=5`