# Understanding induced emfs

1. Feb 11, 2012

### TheLil'Turkey

So if a circuit goes once around an extremely long solenoid whose changing current causes an induced emf of 360 V (in the circuit) at a particular time, does that mean that regardless of the shape of the circuit, the induced emf will be 1 V per degree? If the circuit has only one resistor whose beginning and end make a 1 degree angle with the center of the solenoid, does that mean that the potential difference across that resistor is 359 V at that moment in time?

2. Feb 12, 2012

### jambaugh

That's right, provided the circuit path is close to the solenoid relative to its length.

... another qualifier, the resistance needs to be high enough so that the induced current is insignificant. There's a self inductance effect in the circuit, and for that calculation, shape DOES matter.

Last edited: Feb 12, 2012
3. Feb 12, 2012

### TheLil'Turkey

Oh ya! I didn't think about self-inductance; I think that's the next thing I learn about. Thank you.

This should be taught better in 1st year physics courses.