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 = 1.29, uniformly covers the top of a glass plate, n = 1.64. 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?
film-glass
at both interfaces
at neither interface
air-film
omit
Question 2
What is the wavelength of green, 557-nm light as it travels through the film?
340 nm
557 nm
432 nm
719 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?
108 nm
216 nm
279 nm
139 nm
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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?
108 nm
139 nm
216 nm
279 nm
omit
Question 5
In general, when green light is removed from white light, the film would appear to be which color?
yellow
cyan
magenta
grey
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Question 6
What is the frequency of the green light as it travels through the film?
6.95 x 10
-4
hz
1.3 x 10
20
hz
4.18 x 10
14
hz
5.39 x 10
14
hz
omit
Question 7
If the glass plate is 26 centimeters thick, how many seconds would be required for the transmitted beam to travel through the glass?
8.67 x 10
-10
sec
1.8 x 10
-12
sec
1.56 x 10
-12
sec
1.26 x 10
-12
sec
1.42 x 10
-9
sec
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