Michael Faraday unsuccessfully attempted to measure the potential difference acr
ID: 1390064 • 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 2.1m/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.
A) What is the magnitude of the potential difference?
Explanation / Answer
Induced emf = B*v*L*sin(theta) (here theta is the angle between B and v)
= 50*10^-6*2.1*200*sin(90)
= 0.21 volts or 21 mV <<<<<<<------------Answer