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 = 1.32, uniformly covers the top of a glass plate, n = 1.51. 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
air-film
at neither interface
film-glass
omit
Question 2
What is the wavelength of blue, 475-nm light as it travels through the film?
475 nm
360 nm
627 nm
315 nm
omit
Question 3
At what minimum non-zero thickness of the film will the intensity of the blue light reflected back into the air be a maximum?
119 nm
180 nm
238 nm
90 nm
omit
Question 4
At what minimum non-zero thickness of the film will the intensity of the same blue light reflected back into the air be a minimum, or experience destructive interference?
180 nm
119 nm
90 nm
238 nm
omit
Question 5
In general, when blue light is removed from white light, the film would appear to be which color?
magneta
yellow
grey
cyan
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Question 6
What is the frequency of the blue light as it travels through the film?
4.78 x 10
14
hz
8.34 x 10
-4
hz
6.32 x 10
14
hz
1.08 x 10
20
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?
1.31 x 10
-9
sec
1.82 x 10
-12
sec
8.67 x 10
-10
sec
1.16 x 10
-12
sec
1.56 x 10
-12
sec
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