A straight wire of length
Is oriented east-west and is in a magnetic field B pointing north.The wire is moving downward at a constant speed v.Which end of the rod is positively charged?
A) neither
B) the east end
C) the west end
D) both ends

Question

A straight wire of length 
Is oriented east-west and is in a magnetic field B pointing north.The wire is moving downward at a constant speed v.Which end of the rod is positively charged?
A) neither 
B) the east end 
C) the west end 
D) both ends

Quizplus · Accepted Answer

When a straight wire moves through a magnetic field, an electric field is induced along the wire. This electric field causes charges to move within the wire, resulting in a potential difference between the two ends of the wire.

In this case, the wire is moving downward, which means that the charges will move towards the west end of the wire (since it is moving in a direction perpendicular to the magnetic field). The west end of the wire will therefore be at a higher potential than the east end, and will be positively charged relative to the east end.

Therefore, the correct answer is B, the east end of the wire is negatively charged.

A Straight Wire of Length