# Faraday's Law and Phase Shift

I did an experiment with two solenoids, one inside the other. The inner solenoid was hooked up to an AC power source and ammeter. The outer coil had a voltmeter. This is a faraday's law experiment. Because the current is changing, we can find a formula for the emf. Here are my math steps:
View attachment untitled-1.pdf
So the phase shift for the emf minus the phase shift for the current should give pi/2, but it doesn't! The values I got were (1.103-1.977)=-0.874

What is going on?

Related Other Physics Topics News on Phys.org
NascentOxygen
Staff Emeritus
How did you measure the phase relation of current to voltage?

How did you measure the phase relation of current to voltage?
Loggerpro graphed both simultaneously (using a sin function for each). The general form for each equation was Asin(Bt+C)+D. I found C for each graph and then took the difference. Does that answer your question?

NascentOxygen
Staff Emeritus
What size were the solenoids and how many turns? Was the excitation 60 Hz? What value (roughly) of voltage in the sensing coil did you experience?

I can give you all of the information I have if it will help, but conceptually the exact numbers shouldn't matter, right?

Yes, 60 Hz

number of turns of outer coil- (2920 pm 1)
number of turns of inner coil-(235 pm 1)
diameter of outer coil-(3.4200E-2 pm 7.8E-5) meters
diameter of inner coil- (1.7300E-2 pm 7.8E-5) meters
Length of inner coil- (12.000E-2 pm 7.8E-4) meters
Length of outer coil- (11.000E-2 pm 7.8E-4) meters

All 95% tri pdf

Emf max=2.270V

I also have values for the resistance, capacitance and inductance (from the manual, not from measurement)

Outer coil #29 wire, approx .29mm

Inductance: 63 pm 3 mH
Resistance 76 pm 2 Ω
Capacitance: 124 pm 2 pF

Inner coil #18 wire approx 1mm

Inductance: 78 pm 22 μH
Resistance: 0.4 pm 0.1 Ω
Capacitance: 142 pm 2 pF

I have a suspicion that this has to do with the resistance of the coils, but I still don't understand why or how the model I used is flawed. The predicted result was almost a perfect match with the actual result except for this shift.

NascentOxygen
Staff Emeritus