Energy of Toroidal Solenoid

Homework Statement

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N=600 (number of loops)
a1=200mm
a2=240mm
h=40mm
δ=1,5mm or l0
S0=1,1*S (Cross sectional area)
B0=1,2T

I need to find energy of toroid and currect going through it.
Solution: W=4,08J, I=6,44A

2. The attempt at a solution

So far I managed to calculate S and S0:
S=(a2-a1)*h
S=0,0016m2
S0=1,1*S
S0=0,00176m2

I tried to find energy using this formula but it's not correct:
W0=B02*S0*l0/2*μ0
W0=1,51J

W=B*H*S*(l-l0)/2 (B and H are from the graph)
W=4,76J

Formula for current is I=NH/l but since nothing is correct I didn't bother to try and calculate it.

rude man
Homework Helper
Gold Member
I see nothing wrong with your formula for W0 and W unless you made an arithmetic error which I suspect you did. For example, I got W = 2.34J.
Your formula I=NH/l is wrong however so not using it was ironically a good move!

Last edited:
Never mind. I figured it out. Thanks !