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

  • Thread starter Thread starter AyooNisto
  • Start date Start date
Join the discussion
Registration is free. Start your own thread to ask a follow-up.
Sign up Log in
4 replies · 9K views
AyooNisto
Messages
16
Reaction score
0

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
 
Last edited:
Physics news on Phys.org

Discussion

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?
 
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.