Biot-Savart Law. 1. Given a flat circular coil with N turns (a large number) of wire carrying a current I. The turns are
Posted: Wed Mar 09, 2022 9:21 am
question many times.
If you copy, I will report. But if you do it by yourself,
seriously, no matter correct or wrong, I will thunb you
up.
It's a fair question, not too complicated, earn it by yourself.
Please.
Biot-Savart Law. 1. Given a flat circular coil with N turns (a large number) of wire carrying a current I. The turns are spread uniformly over a flat surface from the inner radius a to the outer radius b. The same setup as in assignment #2, problem No.1. p²dr NI From B-S Law, BA(z)= where K = 2 b-a IdZ UK ģ (r2 a + z2)3/2 > p=a b (i) In this problem you are asked to find the approximate B (2) at any point z where (z> b) but not (z >> b). There will be lots of terms in the series expansion. It is understandable that you may even not get the correct answer. Be very patient, neat, and try your best. It turns out that 0 is zero, so keep () as the first correction term and ignore terms smaller than (0) (ii) Determine B, (z <a) where a is finite and not approaching zero. Once again keeps only two largest terms as in ☺ and leave out smaller terms. Note that here z <r. rédr z+r? r r The following is useful. Siz +r?)? = ln (** + Z Z n(n-1) (1+x)" =1+nx + n(n-1)(n-2) .x² + x +... n can be a fraction, positive or negative, 2! 3! 1 1 1 1 and ln(1+x)= x- -X2 + x- rt +-X |x|<1 2 3 4 5 (a+b+c)2 = a² +b+c? + 2ab + 2ac + 2bc a = x, b=x?, c=x+. 1 2 4 1 I 1 throw out terms with power 2 6. Power of 2 4 6 3 5 6 .. keep only 4 terms. (a+b+c)} = a + b3 +c? +3(ab+ ab? +a’c+abe)+3(abc + acé +b+c+bc) 1 2 4 I 1 1 1 I 个 1 1 个 个 1 throw out power 6 power of 36 12 4 5 6 7 7 9 8 10 keep only 3 terms