Need help on 3b and all of 4

here's what I did for 3b... i thought it was right, but its not, please tell me what i did wrong.
it says outside of the solenoid the magflux is negligible, so do we ignore the area of the box?
fluxmag=(B at 4s)*pi*r^2
(fluxmag/4sec)*N=emf
emf/R

sorry if that's confusing.

11/25/2005 11:27:43 PM

I still haven't gotten the right answer for 3b either. I've been trying:

I* R = N*A*(0.6* t)

11/26/2005 3:18:24 PM

yeah i need help too, this shit sucks

11/27/2005 5:49:39 PM

bttt

11/27/2005 7:07:13 PM

up

11/27/2005 11:40:42 PM

anyone figure this one out yet it does suck but i think there is just one or two things i am doing wrong

11/28/2005 12:39:41 AM

3b: Try This.... .6*t*n*Pi*r^2

4: Find the magnetic field at the center of coil 2 due to coil one using the exact formula
B=10^-7*N*(2*pi*r^2*I)/((z^2+r^2)^(3/2))
where r is the radius of coil 1, N is the number of turns in coil 1, and z is the distance between centers. You'll have to do this twice, once for the current at t=0 and once at t=whatever other time they give you.
For the flux at t=0:
Multiply your magnetic field using current from t=0 by the area of coil 2 pi*r^2. Don't multiply by the number of turns in coil two since they only want it for one turn.

For flux at t2, repeat above steps using the magnetic field found with the second current instead of the first.

emf of one turn of the coil: emf = -(change in flux)/(change in time) so subtract the two fluxes that you found and divide them by the time interval.

For the voltmeter reading, multiply your emf by the number of turns in coil 2

Non coulomb E field in coil 2: use emf=EL where L is the circumfrence of the coil. Use the emf for just one turn of the coil and divide it by 2*pi*r

For the checkboxes, the key word there is "constant." If the current is constant then the magnetic field is constant. Only 2 boxes get checked.

11/28/2005 12:44:30 AM

what is .6

11/28/2005 12:46:58 AM

.6 = (6/10) ?

[Edited on November 28, 2005 at 12:53 AM. Reason : not sure what else to say... ]

11/28/2005 12:52:44 AM

what i mean is , is .6 suppose to be the B in the formula

11/28/2005 1:03:14 AM

also how in the hay did you get that formula

11/28/2005 1:24:47 AM

.6*t is the derivative of your B formula

11/28/2005 4:01:39 PM