Question

A horizontal rod (oriented in the east-west direction) is moved northward at constant velocity through a magnetic field that points straight down. Make a statement concerning the potential induced across the rod.

a. The east end of the rod is at higher potential than the west end.
b. The bottom surface of the rod is at higher potential than the top surface.
c. The top surface of the rod is at higher potential than the bottom surface.
d. The west end of the rod is at higher potential than the east end.
e. The potential is uniform.

Answer 1

The potential difference across the rod is uniform because there is no change in magnetic flux.

Step-by-step explanation:

The potential difference between the ends of the rod is determined by the magnetic force acting on the moving charges in the rod, which induces an electric field. In this case, the rod is moving northward through a magnetic field that points straight down. According to Faraday's law of electromagnetic induction, the potential difference across the rod is proportional to the rate of change of magnetic flux. Since the rod is moving horizontally and perpendicular to the magnetic field, there is no change in magnetic flux, and therefore no potential difference induced across the rod. The correct statement is option e: The potential is uniform.

Answer 2

a. The east end of the rod is at higher potential than the west end.

Step-by-step explanation:

The horizontal rod is oriented in the east-west direction. This means that applying right hand rule, the current will flow from the east to the west. Now, if we assume tat it is a closed loop, we know from polarity of voltage that current usually flows positive to negative terminal within a circuit.

This means the east is at a largely positive terminal while the west is at a largely negative terminal.

Thus, we can say that the east end of the rod is at higher potential than the west end of the rod.