Physical Optics Studyguide

[Joe Ghiorzi]

Whats on the Quiz?

Double slit diffraction
Fringe equations for light and dark fringes (x=(m*λ*L)/d)
Where:
 M= number of slits from brightest center slit
 λ= wavelength
 d= distance between slits
 x= distance between fringes on screen
 L= distance between slits to screen

Must Know Relationships!
 X is directly proportional to L
 X is directly proportional to λ
 D is inversely proportional to X
 Double slit diffraction is caused by constructive and destructive interference, creating light and dark spots.
 Node: where a crest meets a trough, destructive interference.
 Antinode: Where a crest meets a crest (or a trough meets a trough), constructive interference.
 Particles do not diffract (or interfere), however, waves do.

Thin Film/iridecence
n=(λm1)/(λm2)
Where N is the index of refraction, and the λm is the wavelenght of the light traveling in the material. If you do not know that value, You can determine the wavelenght by using the wave speed equation (v=f λ) where the velocity is equal to the frequency times the wavelenght and the N=c/v equation where the refractive gradient is the speed of light in a vacuum over the speed of light in a material.

Credits to SwagPimp: "For thin film interference, the optimum wavelength for a thin film in air is equal to 4nt, where n is the refraction index and t is the thickness of the film."

 In order for films to show color, the incident ray must be near 0 so the rays are close enough to interfere, and they must be “in phase” so the waves constructively interfere.
 When light passes through an object, some light reflects, some refracts, and some passes through.

Polarization of light
 Polarization of light:
 Light is naturally biplane (have both a horizontal and vertical component, all directions).
 Polaroid filters are able to block one orientation, “polarizing” the light and changing its orientation.
 Polarization only works with waves, as a particle would just go straight through.


Photoelectric Effect
Energy=Planks constant*Frequency. Planks constant = 6.63*10^-34. Nature of Photons. The work function is the same equation except frequency is replaced with the minimum threshold frequency (lowest frequency that will emit electrons)

Matter Waves/ de Broglie Waves
All matter has wave properties. It’s a hard concept to wrap your head around. The wavelenght of a moving object can be discribed by λ=h/(m*v) where h is equal to Planks constant, m is mass, and v is velocity. Notice mass*velocity is momentum. Therefore, wavelenght is inversely proportional to momentum

Another contribution from SwagPimp: BIG EQUATION TO REMEMBER HERE! hf (proton energy) = KE (kinetic energy of electron) + W (work function)

Heres a great link explaining Matter waves, Credits to SwagPimp: https://www.facebook.com/l.php?u=http%3A%2F%2Fwww.colorado.edu%2Fphysics%2F2000%2Fquantumzone%2Fdebroglie.html&h=_AQHMnu4c


If you have more to add, Post below and Ill add it to the studyguide

[SwagPimp]

For thin film interference, the optimum wavelength for a thin film in air is equal to 4nt, where n is the refraction index and t is the thickness of the film.

[Kobe24]

These are all the equations which we need to know and their explanations

E= hf

E is the energy of the photon. H is Planck's constant and f is frequency.

V=Lf

V is the speed of light in a vacuum. L is actually lambda, but that symbol's not on here and f is frequency. Note that L is in nm and V is in m. Be sure to convert units here. there are one million nm in a meter

L= h/mv

wavelength is equal to Planck's Constant divided by (mass x volume). This means that anything with a mass and a volume has a wavelength. Even a bowling ball.

mL = dx/Li

Over here note that m is the number out from the center of the image on the screen. L is the wavelength, and dx/L is literally equal to (distance between slits * distance between dark and light)/(distance from slits to screen)

n = c/v

n is the index of refraction, and it's equal to (speed of light in a vacuum)/(speed of light in a medium)

n = Lo/L

the index of refraction is equal to the wavelength of light in a vacuum divided by the wavelength of light in the medium.

From the last two equations it can be determined that c/v = Lo/L

Yeah. So that's all I have to say.

Oh and Go Lakers

[SwagPimp]

Joe, it's SwagPimp, not SuperPimp.

[Joe Ghiorzi]

Dang it, oh well. ill change that.

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