Magnetism help please!!!!!!?

Question

Solenoids produce magnetic fields that are relatively intense for the amount of current they carry. To make a direct comparison, consider a solenoid with 55 turns per centimeter, a radius of 1.07 cm, and a current of 0.230 A.

(a) Find the magnetic field at the center of the solenoid.

(b) What current must a long, straight wire carry to have the same magnetic field as that found in part (a)? Let the distance from the wire be the same as the radius of the solenoid, 1.07 cm.

Answer 1

(a)

B(solenoid) = μ. * n * I.

μ. = (4 * π * 10^7) Tm/A

n = 55turns/cm * 100cm/m = 5500turns/m

I. = 0.23A

B(solenoid) ~= 1.6 * 10^-3 T

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(b)

B(l,s wire) = (μ. * I)/(2πR) --> I = B(l,s wire) * (2πR)/μ.

μ. = (4 * π * 10^7) Tm/A

I = ?

R = 1.07cm = 0.0107m

I ~= 85.05A