1. The problem statement, all variables and given/known data In my ab, we were supposed to obtain the horizontal component of the earth's magnetic field by measuring the period of oscillation of a bar magnet in a known field using the Helmholtz coils, a resistor, and an AC power amplifier. Now during this experiment I had issues with the measuring the period. The reason for so, is because my period of oscillation when applying 1 voltage to the coils would be higher than no applied voltage. And yet when I apply 2, 3, 4, or 5 voltages to the initial 0 applied voltage of the Helmholtz coils, the period of oscillation would decrease (like it's supposed to). Therefore, my question is: Why is it when I apply 1 voltage to the Helmholtz coils the oscillation slows down, but when I apply additional voltage to that, the oscillation will speed up? 2. Relevant equations 3. The attempt at a solution I don't understand why it would slow down only when I add the 1 voltage, and not when I add the additional voltages. Therefore, I would know I did something completely wrong. However, according to my Lab instructor I did everything correctly.