Question

Phys1141: Physics for Engineering and Scientists 11/6/2019 Chapter 29 Worksheet 6. Consider a current car isicer a current carrying coil (i=0.5 A, counter-clockwise as viewed looking down), where the number of coils is 20 and the radius is 5.0 cm. d. Calculate the magnitude of the magnetic moment, for the coil. b. Derive the magnetic field B along the central axis (i.e. in the z direction) of the coil. c. What is the magnetic field at z=20 cm above the coil? d. What is the magnetic field vector at z=40 cm above the coil? e. What is the magnetic field vector at z=80 cm above the coil? f. At what z distance does the magnetic field become effectively independent of the radius, i.e. the magnetic field can be calculated to within 3% when the radius is ignored?

Answer 1

a)

m= NiA

m = 20 * 0.5 * 7(0.05)2 = 0.07854amp.m?

b)

_ Ꭱ172 28 Ꭱ +2}3/2

c) z = 20cm = 0.2m

μο0.5 * 0.052 2(0,052 40 32 3/2 = 0.0896μ

d)

B= 20.05 H.0.5*0.052 20.052 +0.423/2 = 0.01204T

e)

В = 50.05* п,0.5 + 0.052 2(0.052 +08213/2 = 0.00153uT