Michael Faraday unsuccessfully attempted to measure the potential difference acr
ID: 1442196 • Letter: M
Question
Michael Faraday unsuccessfully attempted to measure the potential difference across the River Thames due to the flow of water (which is a good conductor due to dissolved salts) in the earth's field. At Waterloo Bridge, where Faraday made his attempt, the river is 200 m wide and flows eastward at 1.9 m/s . The earth's magnetic field here has a magnitude of 50 T and is tipped 65 from the horizontal, so it has both horizontal (north) and vertical (down) components.
Part B
What is the magnitude of the potential difference?
Express your answer to two significant figures and include the appropriate units.
Explanation / Answer
magnitude of potential difference is e = B*l*v*sin(theta)
e = 50*10^-6*200*1.9*sin(65) = 0.01721 V = 17.21 mV