# Electromagnetic Induction

1. Apr 24, 2010

### lha08

1. The problem statement, all variables and given/known data
So in my textbook, they talk about have 2 coils; a primary coil that is connected in series with a battery and a switch, and a secondary coil in which is connected to a galvanometer. Now it says that when the switch in the primary circuit is closed, the meter in the secondary deflects for an instant. And when the switch is opened, the meter again has a momentary deflection.
I'm trying to understand it and this is what i think but not sure if it's correct: like when they close the switch, a current begins to build up in the primary circuit and begins to create a magnetic field. In the secondary circuit, since it's beginning to feel the effects of the magnetic field from the primary circuit, it wants to create an induced current and induced magnetic field in order to sort of negate the effects that it's experiencing. So if the magnetic field begins forming from the primary circuit and is directed downwards,then the secondary circuit will create an induced magnetic field upwards in order to them to sort of cancel...does this make sense? Am I confusing the terms induced current and induced magnetic field?? :S
Thanks

2. Relevant equations

3. The attempt at a solution

2. Apr 24, 2010

### rootX

1)
When switch is closed, first coil starts building magnetic flux in the second coil which initially was 0
2)
Changing flux in the second coil produces current which tries to resist the change
3)
You see change in the meter
4)
Once the flux is fully established it does not change longer thus no further observation

When switch is opened, same thing happens flux goes for full to 0