A pair of adjacent coils has a mutual inductance of 1.5. H. If the current in one coil changes from 0 to 20 A in 0.5 s, what is the change in flux linkage with the other coil?

Explanation

Mutual inductance of a pair of coils, `mu` = 1.5 H
Initial current, `I_(1)` = 0 A
Final current `I_(2)` = 20 A
Change in current, `dI=I_(2)-I_(1)=20-0=20 A`
Time taken for the change, t = 0.5 s
Induced emf, `e=(dphi)/(dt)` ….(1)
Where `dphi` is the change in the flux linkage with the coil. Emf is related with mutual inductance as:
`e=mu(dI)/(dt)`
Equating equations (1) and (2), we get
`(dphi)/(dt)=mu(dI)/(dt)`
`dphi=1.5xx(20)`
=30 Wb
Hence, the change in the flux linkage is 30 Wb.