PHYSICS · Single correct · AP · Physics 2: Algebra-based · Magnetism and Electromagnetism · Magnetism and Electromagnetism
Problem
A positive point charge moves due west. A positive test charge is located directly behind it on the same line of motion and is also moving due west with the same speed. Which of the following best describes the magnitude of the magnetic force on the test charge due to the source charge?
(a) It is non-zero and attractive because the two moving charges act like parallel currents that attract each other.
(b) It is zero.
(c) It equals 4πr2μ0q2v2.
(d) It is maximum because the velocity vector and the line joining the charges are parallel.