Question

Two coils have a mutual inductance of 5 mH. If the current in the first coil changes by $3A$ in $0.02$second, then the induced emf in the second coil is

• A. $-0.75V$
• B. $-0.75mV$
• C. $-1.5V$
• D. $-750V$

Answer 1

The correct option is A $-0.75V$

Flux linking the secondary coil due to current in primary $=M{i}_1$

induced emf in the secondary coils$=-$rate of change of flux

$=-M\frac{△i_1}{△t}$
$=-5\times \frac{3}{0.02}$
$=-0.75V$