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- Wave optics
- Thin film interference
Step 6.
Solve the appropriate equation for the quantity to be determined (the unknown), and enter the knowns . Slits, gratings, and the Rayleigh limit involve equations.
Step 7.
For thin film interference, you will have constructive interference for a total shift that is an integral number of wavelengths. You will have destructive interference for a total shift of a half-integral number of wavelengths . Always keep in mind that crest to crest is constructive whereas crest to trough is destructive.
Step 8.
Check to see if the answer is reasonable: Does it make sense? Angles in interference patterns cannot be greater than
, for example.
Test prep for ap courses
Which of the following best describes the cause of thin film interference?
- Light reflecting from a medium having an index of refraction less than that of the medium in which it is traveling.
- Light reflecting from a medium having an index of refraction greater than that of the medium in which it is traveling.
- Light changing its wavelength and speed after reflection.
- Light reflecting from the top and bottom surfaces of a film.
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A film of magnesium fluoride (
n = 1.38) is used to coat a glass camera lens (
n = 1.52). If the thickness of the film is 105 nm, calculate the wavelength of visible light that will have the most limited reflection.
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Section summary
- Thin film interference occurs between the light reflected from the top and bottom surfaces of a film. In addition to the path length difference, there can be a phase change.
- When light reflects from a medium having an index of refraction greater than that of the medium in which it is traveling, a
phase change (or a
shift) occurs.
Conceptual questions
How is the difference in paths taken by two originally in-phase light waves related to whether they interfere constructively or destructively? How can this be affected by reflection? By refraction?
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Is there a phase change in the light reflected from either surface of a contact lens floating on a person’s tear layer? The index of refraction of the lens is about 1.5, and its top surface is dry.
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In placing a sample on a microscope slide, a glass cover is placed over a water drop on the glass slide. Light incident from above can reflect from the top and bottom of the glass cover and from the glass slide below the water drop. At which surfaces will there be a phase change in the reflected light?
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An inventor notices that a soap bubble is dark at its thinnest and realizes that destructive interference is taking place for all wavelengths. How could she use this knowledge to make a non-reflective coating for lenses that is effective at all wavelengths? That is, what limits would there be on the index of refraction and thickness of the coating? How might this be impractical?
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Questions & Answers
sound waves can be modeled as a change in pressure ,why is the change on in pressure used and not the actual pressure
I am a university student of Myanmar.I am first year,first semester.I want to learn about physics.
Maung
two charges qA and qB are separated by a distance x. if we double the distance between the charges and triple the magnitude of the charge A, what happens to the magnitude of the force that charge A exerts on charge B.
what happens to the magnitude of the force that charge B exerts on charge A
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force is a pull or push action on an object or a body.
joseph
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Frederick
numerical chapter number 3
a reflected ray on a mirror makes an angle of 20degree with the incident ray when the mirror is rotated 15degree what angle will the incident ray now make with the reflected ray
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Roofs are sometimes pushed off vertically during a tropical cyclone, and buildings sometimes explode outward when hit by a tornado. Use Bernoulli’s principle to explain these phenomena.
Plz answer the question ☝️☝️
Aliraza
what's the basic si unit of acceleration
Explain why the change in velocity is different in the two frames, whereas the change in
kinetic energy is the same in both.
Insulators (nonmetals) have a higher BE than metals, and it is more difficult for photons to eject electrons from insulators. Discuss how this relates to the free charges in metals that make them good conductors.
Is the photoelectric effect a direct consequence of the wave character of EM radiation or of the particle character of EM radiation? Explain briefly.
Muhammad
Determine the total force and the absolute pressure on the bottom of a swimming pool 28.0m by 8.5m whose uniform depth is 1 .8m.
how solve this problem?
Foday
P(pressure)=density ×depth×acceleration due to gravity
Force =P×Area(28.0x8.5)
Fomukom
for the answer to complete, the units need specified why
That's just how the AP grades. Otherwise, you could be talking about m/s when the answer requires m/s^2. They need to know what you are referring to.
Kyle
Source:
OpenStax, College physics for ap® courses. OpenStax CNX. Nov 04, 2016 Download for free at https://legacy.cnx.org/content/col11844/1.14
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