Four identical point charges W, X, Y

PHYSICS · Single correct · AP · Physics 2: Algebra-based · Magnetism and Electromagnetism · Magnetism and Electromagnetism

Problem

Four identical point charges W, X, Y, and Z move such that each produces a magnetic field at point O. The speed

v

, distance

r

to O, and angle

\theta

between the velocity vector and the line to O are listed below. Charge

v

\!(10^{6}\,\text{m/s})

r

(m)

\theta

W 1.0 0.05

90^{\circ}

X 2.0 0.10

90^{\circ}

Y 1.5 0.05

30^{\circ}

Z 1.0 0.07

90^{\circ}

Rank the magnetic field magnitudes at O produced by the charges from largest to smallest. (a)

W > X > Y > Z

(b)

W > Y > Z > X

(c)

X > Y > W > Z

(d)

Y > W > Z > X