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Q & A: voltage on mercury flowing in magnet

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Most recent answer: 02/24/2015
Q:
Consider a thin glass tube (think bulk section of a typical eyedropper) with a magnetized rod coiled around it; liquid is pumped from a reservoir into one end of the tube and allowed to free drain from the other end.In this scenario, would a potential difference be observed between the liquid mercury in the reservoir and the mercury exiting the tube?
- Zigz (age 37)
Australia
A:

To a first approximation, no. The Lorentz force on the charge carriers is at right angles to both the field and to the carriers' velocity. The velocity here is along just the direction along which you're interested in voltage differences, so it won't make any. Right at the ends of the tube where there's some radial velocity you might pick up a bit of voltage, depending on the details of the field configuration.

Mike W. 


(published on 02/24/2015)

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