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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omit
Question 1
A thin film, n = 1.4, uniformly covers the top of a glass plate, n = 1.62. 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
film-glass
at neither interface
air-film
omit
Question 2
What is the wavelength of green, 516-nm light as it travels through the film?
722 nm
369 nm
516 nm
319 nm
omit
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?
129 nm
184 nm
258 nm
92 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?
258 nm
129 nm
184 nm
92 nm
omit
Question 5
In general, when green light is removed from white light, the film would appear to be which color?
magenta
grey
yellow
cyan
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Question 6
What is the frequency of the green light as it travels through the film?
4.15 x 10
14
hz
5.81 x 10
14
hz
1.11 x 10
20
hz
8.14 x 10
-4
hz
omit
Question 7
If the glass plate is 28 centimeters thick, how many seconds would be required for the transmitted beam to travel through the glass?
1.81 x 10
-12
sec
1.94 x 10
-12
sec
1.51 x 10
-9
sec
1.24 x 10
-12
sec
9.33 x 10
-10
sec
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