Recently, I've been studying AC circuits and have developed a
couple questions. I think I worked out an answer to the first,
but I don't know about the second. First, since light bulbs in
houses are powered by AC current, why do we not see them
flicker? Assuming they obey Ohm's law, the current through them
is in phase with voltage, and so it must be 0 twice every
period. My guess is that 60 Hz or 50 Hz used in most countries
is simply so fast that our eyes don't register the flicker?
Second, this question concerns complex impedance and inductors/
resistors in circuits. Let's say we have a variable inductor in
series with a resistor. Supposedly this is an example of a
light-dimmer, because if we increase the inductance, then there
is a larger voltage drop across it because its reactance is jωL.
What I don't understand is that since the voltage is AC, and the
voltage across an inductor is L*dI/dt, wouldn't there be points
in the cycle that the voltage across the inductor drops to 0,
and then the voltage across