(Original post by lyricalvibe)
in the cgp book says ( i'm paraphrasing here) " when a magnet does a half turn, the direction of the magnetic field through the coil reverses.meaning voltage reverses.meaning current flows in the opposite direction around the coil of wire... if the magnet keeps turning in the same direction the voltage ( and hence the current) will keep reversing every half turn-> AC"
you seem to be ready though, i'm no way near
still gotta do majority of p4 and whole of p5 again
i hate physics -_-
Yes. The current and voltage technically reverse to produce the current. This does not mean that when you put ac through a wire it will go one direction for a bit and then suddenly turn around and go back and forth.
The current is produced as an alternating current due to the reversal of the current. In a wire..the current moves in one direction. You're basically over complicating things
(Original post by romaiseb)
Hi, thanks for this! The only thing that I can't get my head around is that if resistance is lower
, then it should be easier
for current to flow
to the light bulb (???) - so in light, when resistance is low, the current should flow easier to the light bulb? (and vice versa for LDRs in the dark...)
Yes, resistance is low and current does flow easier.
whether or not it is easy for current to flow is slightly irrelevant. The more resistance, the harder it is for the current to flow and so the current has to work more on the wire. Think about it this way. You have a swimming lane, it's completely free of any obstacles. It is easy to swim through, you aren't exerting much energy or doing much work. The resistance is low.
Then picture this, there are obstacles in the water. You're working harder to swim through, you're exerting more energy, doing more work. More energy is being put into the pool as heat energy.
In this way, increased resistance is like water with obstacles. The current (swimmer) has to work harder and so does more work, more energy is transferred and the light will switch on.
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