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Finding induced emf of solenoid 
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#1
Mar509, 10:24 PM

P: 7

1. The problem statement, all variables and given/known data
A 800turn solenoid, 18 cm long, has a diameter of 2.9 cm. A 15turn coil is wound tightly around the center of the solenoid. If the current in the solenoid increases uniformly from 0 to 3.1 A in 0.28 s, what will be the induced emf in the short coil during this time? 2. Relevant equations Emf=delta_flux/delta_t 3. The attempt at a solution I keep getting the wrong answer. Originally I just plugged in 800 and 15 for the n's, but then I used turns per meter. Both were wrong. I think I may be using the wrong equation. Any help would be appreciated! 


#2
Mar509, 11:36 PM

HW Helper
P: 2,250

Hi number14,



#3
Mar609, 12:19 AM

P: 7

I used B=(mu_0 *N*I)/l delta_flux = B*pi*r^2 and
Emf=N * delta_flux/delta_t N=15, I=3.1, l=.18, delta_t=.28 , r=.0145 and I got: 3.6 * 10^5 


#4
Mar609, 12:33 AM

HW Helper
P: 2,250

Finding induced emf of solenoid



#5
Mar609, 01:20 AM

P: 7

B=3.3*10^4



#6
Mar609, 01:23 AM

P: 7

Wait, this time i got 1.2*10^5 . I'm using a calculator that is very finicky.



#7
Mar609, 01:32 AM

HW Helper
P: 2,250




#8
Mar609, 01:46 AM

P: 7

thanks so much for the help, i got the right answer finally!!!



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