G17. Biot-Savart Law for a Circular Coil

MAGNETIC FIELDS - Magnetic Field of a Solenoid

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A 28" diameter coil is connected to 125 VDC at 5 amps. The "B" field is measured using a Gaussmeter. One-half of a Helmholtz coil is used. The Gaussmeter scale is connected to an analog projection meter.

G17 Biot-Savart Law for a Circular Coil

B = (μ₀N*i)/2r

Where N=195 r=0.29m; μ₀=1.26x10^-6 Wb/A-m

i measured to be 4.9A

B = {(1.26x10^-6 Wb/A-m)(195)(4.9A)}/(2*0.29m)
= 20.76x10^-4 Wb/m² = 20.76x10^-4 Tesla

B = 20.76 G

B_measured = 19.6 G (measured at center of coil #1)