Question

A carspark coil developes an induced e.m.f. of 40000 V in the secondary when when current in primary changes form 4 A to zero in `10 mu s`. What is the mutual inductance of the coil ?
A. 0.1 H
B. 0.2 H
C. 0.01 H
D. 0.5 H

Answer 1

Correct Answer - C
`e_(s)=M(dI_p)/(dt)` and `dI_(p)=4-0 = 4A`
`:. M = (e_(s)dt)/(dI_p) = (400 xx 10 xx 10^(-6))/(4)`
`10^(-2)H = 0.01 H`.