I was recently given this question by a friend as part of her homework:
The gist of the question is: Say I have a laboratory induction coil with a primary coil which I can slide in and out of the secondary. The turns ratio on the primary and secondary is assumed to be constant.
So as the question states, when the coil is inserted all the way in, there is a spark produced. When it's only inserted say halfway in (not completely in), there is no spark produced.
However, high school physics tells us that V_1/V_2 is proportional to n_1/n_2, so the voltage ratio should be consistent and the spark should appear regardless of how far the secondary coil is in the primary. Why is it not?