Optics B/C

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Re: Optics B/C

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

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.
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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

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.
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

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

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

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

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.
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

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.
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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