A way to produce a fairly uniform magnetic field over a large accessible region
ID: 1318458 • Letter: A
Question
A way to produce a fairly uniform magnetic field over a large accessible region is with a pair of identical circular loops of wire that share the same axis and are physically parallel to each other, but whose centers are a certain distance apart. Each carries equal current in the same direction. Consider the case in which the loops are are both parallel to the y-z plane, their common axis being the x-axis, and with diameters of 48.0cm . Each carries a current of 4.30A , and they are 30.0cmapart and equidistant from the origin. Suppose a particle of charge +e, where e is the fundamental charge, is at the origin, moving in the +y-direction at speed 2950m/s .
Explanation / Answer
magnetic field B due to each of the wire is B = uoi/2R
so
B = (4*3.14e-7 * 4.3)/(2* 0.24)
B1 = B2 = 1.12 uT
Bnet = B1+ B2 = 2B = 2.25 e-5 T
so
magnetic force on the charge F = qvB
F = 1.6 e-19 * 2150 * 2.25 e-5
F = 7.74 *10^-21 N