Question

A pair of adjacent coils has a mutual inductance of 2.5 H. If the current in one coil changes from 0 to 40 A in 0.8 s, then the change in flux linked with the other coil is then

• A. 100 Wb
• B. 120 Wb
• C. 200 Wb
• D. 250 Wb

Answer 1

The correct option is A 100 Wb

Mutual inductance of a pair of coils,, $M=2.5H$

Initial current, $i_1=0A$

Final current, $i_2=40A$

Change in current, $di=i_2-i_1=40A$

Time taken for the change, $t=0.8sec$

Induced e.m.f, $e=\frac{d\varphi }{dt}=M\frac{di}{dt}$

where $d\varphi$ is the change in the flux linked with the coil.

$⟹d\varphi =Mdi=2.5\times 40=100Wb$

Hence, the change in the flux linkage is $100Wb$.

So, option $(A) is correct.