What is the correct thickness of the foil based on the observed dark lines?

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The problem involves determining the thickness of a metal foil based on the observation of dark lines caused by interference. The formula used is t = mλ, where m represents the fringe number. The calculation initially yields a thickness of 8.05 * 10^-6 meters, which is equivalent to 8.05 micrometers. A misunderstanding regarding unit conversion led to confusion about the final answer. The correct interpretation confirms that the thickness should indeed be expressed in meters.
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Homework Statement


A fine metal foil separates one end of two pieces of optically flat glass, as in Figure 24-33 in the textbook. When light of wavelength 700nm is incident normally, 24 dark lines are observed (with one at each end).

How thick is the foil?

Homework Equations


t = mλ, m = 0,1,2,...

The Attempt at a Solution


because m = 0 corresponds to the edge where the glasses touch m+1 represents the number of the fringe so the thickness of the foil is

d = (1/2)(23)(700nm)
d = 8.05 * 10 ^ -6 this is not the right answer and i don't understand why where am i going wrong
 
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what are the units of your answer?
 
the answer i keep getting is 8.05 * 10^-6 which i guesss would be a micrometer ( i edited that above) which i guess would be but the answer has to be in meters.
barryj said:
what are the units of your answer?
 
I think you are correct.
 
wow yeah, the problem was i wasnt putting in the *10^-6... thanks for your help stupid mistake on my part.
barryj said:
I think you are correct.
 

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