Coefficient of coupling between two coils of self-inductances `L_(1)` and `L_(2)` is unity. It means

Options

A. `50%` flux of `L_(1)` is linked with `L_(2)`
B. `100%` flux of `L_(1)` is linked with `L_(2)`
C. `sqrt(L_(1))` time of flux of `L_(1)` is linked with `L_(2)`
D. None of the above

Answer

B

Explanation

Two coils ace said to be magnetically coupled, if full or a part of the flux produced by one link with the other. Let `L_(1)` and `L_(2)` be the self-inductances of the coils and M be their mutual inductances, then
`k=(M)/(sqrt(L_(1)L_(2))`
When `100%` flux produced by one coil links with the other, then mutual inductance between the two is maximum and is given by
`Msqrt(L_(1)L_(2))`