Question

Coefficient of mutual induction between 2 coils is 0.4 H. If a current of 4A in the primary is cut off in $\frac{1}{15000}$ second, the emf induced in the secondary is

• A. 24 KV
• B. 15 KV
• C. 30 KV
• D. 10 KV

Answer 1

The correct option is A 24 KV

$E=-M\frac{di}{dt}=-M\left[\frac{i_2-i_1}{t}\right]$
$=-0.4\left[\frac{0-4}{\left(\frac{1}{15000}\right)}\right]=1.6\times 15\times {10}^3$
$=24\times {10}^{3}V$
$E=24kV$