Optics B/C

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Re: Optics B/C

Postby UTF-8 U+6211 U+662F » March 2nd, 2018, 1:00 pm

Tom_MS wrote:
UTF-8 U+6211 U+662F wrote:What is the primary difference between gamma and X rays? (Don't say wavelength/frequency/energy since there isn't a defined boundary between gamma and X rays there)

Gamma rays are produced by nuclear processes (like nuclear decay) and particle interactions (like annihilation of particle-antiparticle pairs). X-rays are produced by electrons outside of the nucleus.

Yep, your turn!

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Re: Optics B/C

Postby Tom_MS » March 4th, 2018, 4:05 pm

What is Compton scattering? Is it elastic or inelastic? What general type of EM radiation does it affect? Describe the mechanism by which it functions.

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Re: Optics B/C

Postby c0c05w311y » March 7th, 2018, 11:37 am

Tom_MS wrote:What is Compton scattering? Is it elastic or inelastic? What general type of EM radiation does it affect? Describe the mechanism by which it functions.


Answer:
Compton scattering is scattering of a photon from a charged particle (usually an electron) . It is inelastic: the energy of the photon is decreased after the scattering, since some of the energy goes into recoil of the electron. The electron is treated as free or loosely bound in the math for this. It primarily affects X-rays and gamma rays. With lower energy light, photons might be absorbed completely, causing the photoelectric effect, and with really high photon energy, you can get electron/positron pair production by interaction with the nucleus. Thompson scattering is basically the same thing, except the energy change of the photon is not observable because the energy of the photon is much less than the mass energy of the photon. This is why Compton scattering affects higher energy xray and gamma EMR. The important difference is that Thompson scattering can be explained with classical electromagnetism, while the existence of Compton scattering supports the quantum/particle model of light. Note that both energy and momentum are conserved.

please let me know if i made any mistakes

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Re: Optics B/C

Postby Tom_MS » March 7th, 2018, 3:58 pm

c0c05w311y wrote:
Answer:
Compton scattering is scattering of a photon from a charged particle (usually an electron) . It is inelastic: the energy of the photon is decreased after the scattering, since some of the energy goes into recoil of the electron. The electron is treated as free or loosely bound in the math for this. It primarily affects X-rays and gamma rays. With lower energy light, photons might be absorbed completely, causing the photoelectric effect, and with really high photon energy, you can get electron/positron pair production by interaction with the nucleus. Thompson scattering is basically the same thing, except the energy change of the photon is not observable because the energy of the photon is much less than the mass energy of the photon. This is why Compton scattering affects higher energy xray and gamma EMR. The important difference is that Thompson scattering can be explained with classical electromagnetism, while the existence of Compton scattering supports the quantum/particle model of light. Note that both energy and momentum are conserved.

please let me know if i made any mistakes


Yep you're good (although I don't think photons have mass energy ;) ). Your turn!

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Re: Optics B/C

Postby UTF-8 U+6211 U+662F » March 14th, 2018, 6:57 pm

Restarting this... Why do light waves undergo specular reflection when hitting a mirror but diffuse reflection when hitting a piece of paper?

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Re: Optics B/C

Postby MattChina » March 14th, 2018, 7:27 pm

UTF-8 U+6211 U+662F wrote:Restarting this... Why do light waves undergo specular reflection when hitting a mirror but diffuse reflection when hitting a piece of paper?


Becuase the mirror is flat and the paper is not?
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Re: Optics B/C

Postby UTF-8 U+6211 U+662F » March 14th, 2018, 7:27 pm

MattChina wrote:
UTF-8 U+6211 U+662F wrote:Restarting this... Why do light waves undergo specular reflection when hitting a mirror but diffuse reflection when hitting a piece of paper?


Becuase the mirror is flat and the paper is not?

Sure. Your turn!

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Re: Optics B/C

Postby MattChina » March 14th, 2018, 7:33 pm

Image

A beam of light enters a transparent prism from the air and refracts as shown in the diagram to the right. Find angle Y.
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Re: Optics B/C

Postby UTF-8 U+6211 U+662F » March 14th, 2018, 7:54 pm

MattChina wrote:Image

A beam of light enters a transparent prism from the air and refracts as shown in the diagram to the right. Find angle Y.

Answer
sin 59 = 1.5 sin (90-x)
X = 90 - arcsin(sin 59 / 1.5)
Y = 120 - X = 65 deg

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Re: Optics B/C

Postby MattChina » March 15th, 2018, 3:18 pm

UTF-8 U+6211 U+662F wrote:
MattChina wrote:Image

A beam of light enters a transparent prism from the air and refracts as shown in the diagram to the right. Find angle Y.

Answer
sin 59 = 1.5 sin (90-x)
X = 90 - arcsin(sin 59 / 1.5)
Y = 120 - X = 65 deg


Correct. Your Turn.
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Re: Optics B/C

Postby UTF-8 U+6211 U+662F » March 15th, 2018, 4:15 pm

The ___ approximation is a small angle approximation used in __ optics (sorry, a little bit vague) and ray tracing.

Hint 1
First blank means hitting close to the optical axis

Hint 2
Second blank refers to a mathematician

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Re: Optics B/C

Postby Etan » March 23rd, 2018, 2:37 pm

Here's a question:

If person A is standing 11.25 ft away from a mirror, how far away will there image be?
How far away would person B's image be if they stood 28 ft behind person A?
If the mirror was a concave mirror what would happen to person B's image?
if the mirror was a convex mirror what would happen to person A's image?

I know that it's basically 4 questions and that it's pretty simple but hey, what are ya gonna do?
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Re: Optics B/C

Postby UTF-8 U+6211 U+662F » March 23rd, 2018, 5:02 pm

Etan wrote:Here's a question:

If person A is standing 11.25 ft away from a mirror, how far away will there image be?
How far away would person B's image be if they stood 28 ft behind person A?
If the mirror was a concave mirror what would happen to person B's image?
if the mirror was a convex mirror what would happen to person A's image?

I know that it's basically 4 questions and that it's pretty simple but hey, what are ya gonna do?


Answer
1) 22.5 ft
2) 50.5 ft from A, 78.5 ft from B
3) If past one focal length, it would be inverted, real, and smaller. If within one focal length, it would be upright, virtual, and larger.
4) Upright, virtual, smaller

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Re: Optics B/C

Postby UTF-8 U+6211 U+662F » March 31st, 2018, 6:13 pm

Restarting...

Explain the joke in a license plate that says "If this appears blue, you are going too fast."

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Re: Optics B/C

Postby Adi1008 » April 3rd, 2018, 5:50 pm

UTF-8 U+6211 U+662F wrote:Restarting...

Explain the joke in a license plate that says "If this appears blue, you are going too fast."

Answer
Doppler effect. When you're moving towards an object (or it's moving towards you) the wavelengths become shorter (appear bluer)
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