I figured out the first part....I went and re did the lab again and got the max with completely different data. This second part though im getting very off data and I think its because I'm not measuring right with the magnetic sensor....when measuring the magnetic inclination how should I hold...
I just dont know what to do after that thread ended. If its wrong completely or if it was solved and thats why no one else responded haha. Ive been stuck on that and another question for about a week and a half!
sorry the initial attempt was
back emf = (5.6 x 10^-5)[+2.2 - (-2.2)/Δt]
T = 1/f --> 1/2T = 1/f --> 2/f -- > T = 2/20000 = 1.0 x 10^-4 secs
If this is the case then, by subbing, Δt = 1.0 x 10^-4 secs, into the above equation, I get:
back emf = (5.6 x 10^-5)[+2.2 - (-2.2)/1.0 x 10^-4 secs]
This thread is the exact question I have, however I approached it differently, and this is what I got:
n = 2(pie)fL = 2(pie)(20x10^3Hz)(5.6x10^-6H) = 7.04 (ohms)
Then Irms = I/sqrt(2) = 2.2 A / sqrt(2) = 1.56 A
Then Vrms = Irms x n = 1.56A x 7.04 (ohms) = 21.9V
This was an answer added on later to this question in a different thread- -
Okay, so if I am considering a whole period than my currents are actually +4.4 and - 4.4. Additionally, my period is actually just T = 1/f = 1/20000 = 5.0 x 10^-5.
back emf = (5.6 x 10^-5)[+4.4 - (-4.4)/5.0 x 10^-5...
The coil in a loudspeaker has an inductance of L = 56uH (or 5.6 x 10^-5 H). To produce a sound frequency of 20 kHz, the current must oscillate between peak values of +2.2 A and -2.2 A in one half of a period. What average back emf is induced in the coil during this variation...