Practice Problems
Thin Film Interference Glass Coating
Topics:
On this worksheet you will be investigating the basic properties of
thin film interference
revealed in different thicknesses of film on glass.
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Question 1
A thin film, n = 1.37, uniformly covers the top of a glass plate, n = 1.55. If the medium above the film is air, at which of the interfaces (air-film and film-glass) does the light undergo a 180° phase change upon reflection?
at both interfaces
at neither interface
air-film
film-glass
omit
Question 2
What is the wavelength of green, 544-nm light as it travels through the film?
351 nm
397 nm
544 nm
745 nm
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Question 3
At what minimum non-zero thickness of the film will the intensity of the green light reflected back into the air be a maximum?
99 nm
199 nm
272 nm
136 nm
omit
Question 4
At what minimum non-zero thickness of the film will the intensity of the same green light reflected back into the air be a minimum, or experience destructive interference?
99 nm
272 nm
136 nm
199 nm
omit
Question 5
In general, when green light is removed from white light, the film would appear to be which color?
cyan
magenta
yellow
grey
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Question 6
What is the frequency of the green light as it travels through the film?
7.56 x 10
-4
hz
5.51 x 10
14
hz
4.03 x 10
14
hz
1.19 x 10
20
hz
omit
Question 7
If the glass plate is 27 centimeters thick, how many seconds would be required for the transmitted beam to travel through the glass?
1.95 x 10
-12
sec
1.4 x 10
-9
sec
1.18 x 10
-12
sec
9 x 10
-10
sec
1.65 x 10
-12
sec
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