What rules governs the mutual induction

[Harrison G]

Homework Statement

Homework Equations

With what equations i can express the fact that when dc is aplied to transformer there is mutual inductance only when the voltage is turned on or off and there is no positive feed back represented as an infinite inducyion between the 2 coils?

The Attempt at a Solution

 

[BvU]

Faraday's Law on the receiving end
Ampere's law ( coil field ) on the 'sending' end