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 in a magnetic field at a constant velocity, a potential difference is produced between its two ends, causing an electric field to develop.

The direction of this electric field can be determined by the Fleming's right-hand rule. In this situation, the thumb of the right hand points in the direction of the velocity (downward), the index finger points in the direction of the magnetic field (north), and the middle finger points in the direction of the electric field.

Using Fleming’s rule, we can see that the electric field will point towards the east end of the wire, meaning that the east end will be more positively charged than the west end. Therefore, the answer is B) the east end.

A Straight Wire of Length