There are two coils A and B separated by some distance. If a current f 2A flows through A, a magnetic flux of 10-2 Wb passes through B (no current through B). If no current passes through A and a current of 1 A passes through B, What is the flux through A?

Hint: The passing through each coil depends on the mutual inductance.
Step 1: ApplyingthemutualinductanceofcoilAwithrespecttocoilB:
M21=N2ϕ2I1
Therefore,wehave;
Mutualinuctance=10-22=5mH
Step 2:Againapplyingthisformulaforothercase
N1ϕ1=M12I2=5mH×1A=5mWb.