- #1
lenfromkits
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When Fizeau (and Michelson and Morley) measured the fringe shifts that occur when light travels through a moving medium, how exactly (in words) did they deduce the change in velocity? My understand is this:
1) Count the fringe shifts that occur.
2) Calculate what the frequency shift must have been based on those fringe shifts.
3) Calculate what the velocity shift must have been based on the frequency shift.
So, my real concern is with #3. What is the relationship that they used between the frequency and the velocity? Does a 1% increase in frequency translate into a 1% increase in velocity? This is puzzling because "normally" in a vacuum, a frequency change does not mean there is a velocity change (c is constant), so how do they manage to figure out what velocity change would be associated with a frequency change?
Thanks for your help.
1) Count the fringe shifts that occur.
2) Calculate what the frequency shift must have been based on those fringe shifts.
3) Calculate what the velocity shift must have been based on the frequency shift.
So, my real concern is with #3. What is the relationship that they used between the frequency and the velocity? Does a 1% increase in frequency translate into a 1% increase in velocity? This is puzzling because "normally" in a vacuum, a frequency change does not mean there is a velocity change (c is constant), so how do they manage to figure out what velocity change would be associated with a frequency change?
Thanks for your help.