Question

The English Channel runs between England and France. Ocean tides cause the water in the channel to flow to the west and then, sometime later, back to the east. At the narrowest part of the Channel, the Strait of Dover, a straight-line distance of 44 km separates Dover, in England, from Calais, in France. Water flows at a maximum speed of about 1.2 m/s through the strait; it is approximately 30 m deep. At this latitude, the earth’s magnetic field is nearly vertical. We’ll assume that it is vertical, and so points directly toward the center of the earth, with magnitude 45 μT.

a. With the water flowing at its maximum speed, what is the potential difference (magnitude and sign) between Dover and Calais? (In fact, early investigators used the potential difference across a length of undersea telegraph and telephone cable to estimate the flow speed.) b. What is the magnitude of the electric field in the water due to the water's motion?

Answer 1

Step-by-step explanation:

Potential difference is created when a long object of length l moves perpendicular to magnetic field . The potential difference created is

V = Blv where B is magnetic field , l is length and v is velocity of length l .

here V = 45 x 10⁻⁶ x 44000 x 1.2

= 2.376 volt .

b )

Electric field = V / l ; V is potential difference between length l .

= 2.376 / 44000

= 54 x 10⁻⁶ V/m