Optics B/C

Test your knowledge of various Science Olympiad events.
Avogadro
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Re: Optics B/C

Postby Avogadro » March 8th, 2017, 5:59 pm

Lol apparently I'm bad at my own questions. I ran through it again and I got the same answer as Tom and Jon.
Lower Merion 2017
Subtitled: Revenge of the Non-Harriton

Placement Record:

Code: Islip | Conestoga | Tiger | Regionals | States
Out of: 61 | 42 | 36 | 37 | 36

Chemistry Lab: 9 | - | - | 4 | 4
Astronomy: 14 | - | 5 | 10 | 3
Material Science: 12 | 19 | 9 | 5 | 9
Optics: 14 | 7 | 3 | 4 | 2

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Re: Optics B/C

Postby UTF-8 U+6211 U+662F » March 9th, 2017, 5:04 pm

Answer
I'm not 100% sure about this but is it light blue?
Correct! Your turn!

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Re: Optics B/C

Postby jonboyage » March 9th, 2017, 6:59 pm

Briefly explain the phenomenon of tertiary rainbows
I was in a bin

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Re: Optics B/C

Postby Avogadro » March 10th, 2017, 8:18 am

Briefly explain the phenomenon of tertiary rainbows
Not sure how far I should go with this, but I'll give a bit.
Best I Can Come Up With
A tertiary rainbow is the term given to a rainbow produced by light leaving the drop after three reflections. It is generally less bright than one would expect, due to various factors such as glare from surrounding light, light that does not undergo reflection within the drop, etc. Another factor that makes it difficult to see is its angle in relation to the Sun - ~45°.
Lower Merion 2017
Subtitled: Revenge of the Non-Harriton

Placement Record:

Code: Islip | Conestoga | Tiger | Regionals | States
Out of: 61 | 42 | 36 | 37 | 36

Chemistry Lab: 9 | - | - | 4 | 4
Astronomy: 14 | - | 5 | 10 | 3
Material Science: 12 | 19 | 9 | 5 | 9
Optics: 14 | 7 | 3 | 4 | 2

jonboyage
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Re: Optics B/C

Postby jonboyage » March 10th, 2017, 8:48 am

Briefly explain the phenomenon of tertiary rainbows
Not sure how far I should go with this, but I'll give a bit.
Best I Can Come Up With
A tertiary rainbow is the term given to a rainbow produced by light leaving the drop after three reflections. It is generally less bright than one would expect, due to various factors such as glare from surrounding light, light that does not undergo reflection within the drop, etc. Another factor that makes it difficult to see is its angle in relation to the Sun - ~45°.
That's all I was looking for! Your turn.
I was in a bin

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Avogadro
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Re: Optics B/C

Postby Avogadro » March 10th, 2017, 12:23 pm

Why is the sky blue?
Lower Merion 2017
Subtitled: Revenge of the Non-Harriton

Placement Record:

Code: Islip | Conestoga | Tiger | Regionals | States
Out of: 61 | 42 | 36 | 37 | 36

Chemistry Lab: 9 | - | - | 4 | 4
Astronomy: 14 | - | 5 | 10 | 3
Material Science: 12 | 19 | 9 | 5 | 9
Optics: 14 | 7 | 3 | 4 | 2

jkang
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Re: Optics B/C

Postby jkang » March 10th, 2017, 12:59 pm

Why is the sky blue?
Because
sunlight scatters off the molecules in the Earth's atmosphere (Rayleigh scattering). This scattering is effective at short wavelengths, thus the light scattering down is primarily blue.
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Avogadro
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Re: Optics B/C

Postby Avogadro » March 10th, 2017, 1:44 pm

Why is the sky blue?
Because
sunlight scatters off the molecules in the Earth's atmosphere (Rayleigh scattering). This scattering is effective at short wavelengths, thus the light scattering down is primarily blue.
Yup. Your turn!
Lower Merion 2017
Subtitled: Revenge of the Non-Harriton

Placement Record:

Code: Islip | Conestoga | Tiger | Regionals | States
Out of: 61 | 42 | 36 | 37 | 36

Chemistry Lab: 9 | - | - | 4 | 4
Astronomy: 14 | - | 5 | 10 | 3
Material Science: 12 | 19 | 9 | 5 | 9
Optics: 14 | 7 | 3 | 4 | 2

jkang
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Re: Optics B/C

Postby jkang » March 11th, 2017, 11:22 am

A wave has a phase velocity of 2c (where c = the speed of light in a vacuum). How is this possible?
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Avogadro
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Re: Optics B/C

Postby Avogadro » March 13th, 2017, 8:07 am

A wave has a phase velocity of 2c (where c = the speed of light in a vacuum). How is this possible?
Not sure, but
I have two possible explanations: 1. The wave has entered a theoretical material with a refractive index of 0.5. 2. The wave manages to have an incredibly short period.
If neither of those is true then I'm clueless.
Lower Merion 2017
Subtitled: Revenge of the Non-Harriton

Placement Record:

Code: Islip | Conestoga | Tiger | Regionals | States
Out of: 61 | 42 | 36 | 37 | 36

Chemistry Lab: 9 | - | - | 4 | 4
Astronomy: 14 | - | 5 | 10 | 3
Material Science: 12 | 19 | 9 | 5 | 9
Optics: 14 | 7 | 3 | 4 | 2

jkang
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Re: Optics B/C

Postby jkang » March 13th, 2017, 9:36 am

A wave has a phase velocity of 2c (where c = the speed of light in a vacuum). How is this possible?
Not sure, but
I have two possible explanations: 1. The wave has entered a theoretical material with a refractive index of 0.5. 2. The wave manages to have an incredibly short period.
If neither of those is true then I'm clueless.
Sorry, neither are correct. As a hint, phase is the key word here.
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Re: Optics B/C

Postby Adi1008 » March 13th, 2017, 10:22 am

A wave has a phase velocity of 2c (where c = the speed of light in a vacuum). How is this possible?
Not sure, but
I have two possible explanations: 1. The wave has entered a theoretical material with a refractive index of 0.5. 2. The wave manages to have an incredibly short period.
If neither of those is true then I'm clueless.
Sorry, neither are correct. As a hint, phase is the key word here.
I think
The Theory of Relativity says that information cannot travel faster than the speed of light. The refractive index is a measure of the phase velocity of light, which does not carry information, so it is able to be less than 1.
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jkang
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Re: Optics B/C

Postby jkang » March 13th, 2017, 1:07 pm

Not sure, but
I have two possible explanations: 1. The wave has entered a theoretical material with a refractive index of 0.5. 2. The wave manages to have an incredibly short period.
If neither of those is true then I'm clueless.
Sorry, neither are correct. As a hint, phase is the key word here.
I think
The Theory of Relativity says that information cannot travel faster than the speed of light. The refractive index is a measure of the phase velocity of light, which does not carry information, so it is able to be less than 1.
This is correct. Because phase velocity doesn't contain information, it has the ability to travel faster than c. The Wikipedia for refractive index has your answer almost word for word. Your turn!
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Adi1008
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Re: Optics B/C

Postby Adi1008 » March 15th, 2017, 2:12 pm

Sorry, neither are correct. As a hint, phase is the key word here.
I think
The Theory of Relativity says that information cannot travel faster than the speed of light. The refractive index is a measure of the phase velocity of light, which does not carry information, so it is able to be less than 1.
This is correct. Because phase velocity doesn't contain information, it has the ability to travel faster than c. The Wikipedia for refractive index has your answer almost word for word. Your turn!
What is the smallest time delay required between two waves of 400nm light to obtain complete destructive interference?
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Re: Optics B/C

Postby Tom_MS » March 15th, 2017, 3:33 pm

What is the smallest time delay required between two waves of 400nm light to obtain complete destructive interference?
You can answer I just wanted to give it a shot.
I'm getting...
6.67*10^-16 seconds. This is using the distance over time definition of the speed of light with a 200nm distance to create fully destructive interference.


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