Q. Two coils $A\ and\ B$ have coefficient of mutual inductance M = 2H. The magnetic flux passing through coil $A$ changes by 4 Wb in 10 s due to change in current in B. Then
A) Change in current in B in this time interval is 0.5 A
B) Change in current in B in this time interval is 8 A
C) The change in current in B in this time interval is 2 A
D) A change in current of 1 A in coil A will produce a change in flux passing through B by 4 Wb
Explanation
(c) Here, $M = 2H,\ \ d\phi = 4\ Wb,\ dt = 10\ s$
As $\phi\ = M\ i\ $
$d\phi = M\ di$
Or $di = \frac{d\phi}{M} = \frac{4}{2} = 2\ $A
Also, $d\phi = M\ (di) = 2(1)$
= 2 Wb
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.