Two long parallel wires are placed side-by-side on a horizontal table and carry current in the same direction.The current in one wire is 20 A,and the current in the other wire is 5 A.If the magnetic force on the 20-A wire has magnitude F,what is the magnitude of the magnetic force on the 5-A wire? No external magnetic fields are present.
A)4F
B)2F
C)F
D)F/2
E)F/4

Question

Quizplus · Accepted Answer

According to Newton's third law, the magnetic force exerted by one wire on the other is equal in magnitude and opposite in direction. Therefore, the magnitude of the magnetic force on the 5-A wire is the same as the force on the 20-A wire, which is F.

Two Long Parallel Wires Are Placed Side-By-Side on a Horizontal