Optics B/C

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Re: Optics B/C

Postby antoine_ego » Sat Oct 29, 2016 9:45 pm

Just for clarification, when the rules state
All reference materials to be used during all parts of the competition must be initially secured within a 3 ring binder...

does this include materials used for the laser shoot?
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Re: Optics B/C

Postby Unome » Sat Oct 29, 2016 10:05 pm

antoine_ego wrote:Just for clarification, when the rules state
All reference materials to be used during all parts of the competition must be initially secured within a 3 ring binder...

does this include materials used for the laser shoot?

When I competed in Simple Machines this was usually the case (although we didn't really need much reference materials for the lever).
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Re: Optics B/C

Postby jasony123123 » Sun Oct 30, 2016 3:54 pm

On the rules there is no restriction on where along the midline the barrier can be placed. So does that mean the proctor can put the barrier 1 cm away from the laser; or will the placement still be relatively reasonable?

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Re: Optics B/C

Postby chalker » Sun Oct 30, 2016 8:33 pm

jasony123123 wrote:On the rules there is no restriction on where along the midline the barrier can be placed. So does that mean the proctor can put the barrier 1 cm away from the laser; or will the placement still be relatively reasonable?


Well if the barrier is 1cm away from the laser, will ANYBODY be able to get a mirror in there and deflect the beam away? No, hence the supervisor has to allow enough room to put a mirror in there.

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Re: Optics B/C

Postby jkang » Sun Nov 20, 2016 4:42 am

Here's my optics test from the recent UT-Austin invitational (key). If you have any questions about it, feel free to PM or email me!

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Re: Optics B/C

Postby jasony123123 » Sun Nov 27, 2016 2:23 am

Do you think we will need to know the Lensmakers equation

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Re: Optics B/C

Postby Fluorine » Sun Nov 27, 2016 2:40 am

jasony123123 wrote:Do you think we will need to know the Lensmakers equation


In the rules manual it say under section d.v "Division C also lensmaker's equation." So if you are C division 100% yes you should know lensmakers.

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Re: Optics B/C

Postby svora » Mon Dec 05, 2016 10:05 pm

Are we allowed cheat sheets in the written test part of the Optics B event ? If yes, what are the dimensions ?

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Re: Optics B/C

Postby Unome » Mon Dec 05, 2016 10:15 pm

svora wrote:Are we allowed cheat sheets in the written test part of the Optics B event ? If yes, what are the dimensions ?

This is the type of question that can be easily answered by reading the rules. Your coach should have received a copy of the rules when they registered your school's team with the state organization; you can also buy a physical copy yourself ($8 plus shipping) or get the mobile rules app (Apple/Android, $4). Reading the rules thoroughly should always be the first thing you do for any new event.

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Re: Optics B/C

Postby Cloudia » Thu Dec 08, 2016 11:26 pm

Hello :)

This is my first year coaching optics C. My experience with SciOly is with Robotic Arm previously, so I'm new to the theory side of events. My students and I covered all of the non-state/national level theory before they competed in the Cornell Invitational in NY this past weekend.

While I was expecting that my students would struggle with the state/national level theory (lasers, multiple lenses, etc) that the Cornell Invitational is known for, there were questions in which I can't see how they fit within any of this year's optics topics. Alternatively, is it common to see more topics thrown than expected?

I'm hoping that someone may be able to provide me with guidance on whether I need to be teaching this extra material?

For completeness, I'll copy as much of the relevant questions as possible to maintain the context.

So that these questions don't scare students as they did my own, all of the other questions were the type we expected from the optics C rules. These are just the tricky exceptions.

Thank you in advance for any advice that can be offered!

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Question 24. Diagrams are shown for both absorption (first) and emission spectra (second). Differentiate between the two spectra and explain how the second spectrum is produced.

(I have taught absorption spectra, but not emission, and especially not how it's created. Is this required knowledge?)

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Question 25. What is Huygens principle, and how does it relate to the double-slit experiment (assume the width of the slit is less than the wavelength of course)? Again feel free to use drawings as aids to explain.

(I'm not sure which topic this comes under this year?)

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Question 26. Analysis of hydrogen spectral lines from a distant star are measured to have a wavelength of .21107m. However, hydrogen emission lines are measured to be .21106m in a vacuum. How fast is the star travelling in terms of the speed of light (c)? Is this an example of red shift or blue shift?

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Question 27. Give an example of when light acts as a particle, and an example of when it acts like a wave.

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Question 39. A hydrogen electron transitions from n=3 to n=1. Is a photon absorbed or emitted?

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Question 40. What is the photon's energy in eV?

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Question 41. What is the frequency of the photon?

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Question 9. Give the speed of light in each medium, relative to c, the speed of light in a vacuum. Also give the wavelength and frequency light in each medium. Also give the energy of a single photon in each medium. Find the values for all three media (including the initial medium). Assume that the initial wavelength is 635nm.

(Diagram was light entering air and then two mediums with different refractive indexes. My question is whether the photon energy component should be included in this year's material?)

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Question 10. Take the energy values from number 9. Explain any pattern or lack or pattern in the values. Why does this occur?

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Re: Optics B/C

Postby chalker » Fri Dec 09, 2016 12:46 am

Part of the challenge is that individual event supervisors might interpret topics quite differently. There isn't some secret supervisor manual or test bank for them to work with. Also, it's common for tournament directors to utilize faculty members, who don't always pay close attention to the rules since they are used to teaching on these topics and think they should include whatever they typically include in intro college classes. But this is also an opportunity for the students to learn more stuff! In regards to your specific questions:

Cloudia wrote:(I have taught absorption spectra, but not emission, and especially not how it's created. Is this required knowledge?)


I wouldn't expect emission spectra to be included. That said, it's rather trivial to understand the basics of emission spectra if you understand absorption spectra.


Cloudia wrote:Question 25. What is Huygens principle, and how does it relate to the double-slit experiment (assume the width of the slit is less than the wavelength of course)?


This is related to diffraction and is not within the scope of topics listed in the rules.

Cloudia wrote:Question 26. Analysis of hydrogen spectral lines from a distant star are measured to have a wavelength of .21107m. However, hydrogen emission lines are measured to be .21106m in a vacuum. How fast is the star travelling in terms of the speed of light (c)? Is this an example of red shift or blue shift?


Doppler effect / relativity also aren't in the topics list.


Cloudia wrote:Question 27. Give an example of when light acts as a particle, and an example of when it acts like a wave.


Ditto for quantum physics

Cloudia wrote:Question 39. A hydrogen electron transitions from n=3 to n=1. Is a photon absorbed or emitted?


This is borderline acceptable since it relates to absorption spectra

Cloudia wrote:Question 40. What is the photon's energy in eV?
Question 41. What is the frequency of the photon?


But I think this takes the topic far beyond what's intended by the rules.

Cloudia wrote:(Diagram was light entering air and then two mediums with different refractive indexes. My question is whether the photon energy component should be included in this year's material?)

Question 10. Take the energy values from number 9. Explain any pattern or lack or pattern in the values. Why does this occur?


I don't think so.

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Re: Optics B/C

Postby superpenguin666 » Fri Dec 09, 2016 9:55 pm

Hello,
I really need help now, my Optics final (for team selection) is next Wednesday, and I'm not really sure about the optical absorption spectra! I've already posted this question (and now I'm asking it again), but can somebody please give a simple explanation and resources for the optical absorption spectra? I'd appreciate it a lot.
Thanks,
superpenguin666

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Re: Optics B/C

Postby chalker » Fri Dec 09, 2016 10:48 pm

superpenguin666 wrote:Hello,
I really need help now, my Optics final (for team selection) is next Wednesday, and I'm not really sure about the optical absorption spectra! I've already posted this question (and now I'm asking it again), but can somebody please give a simple explanation and resources for the optical absorption spectra? I'd appreciate it a lot.
Thanks,
superpenguin666


Have you tried Wikipedia? It's always a good place to start and points to lots of other resources:

https://en.wikipedia.org/wiki/Absorption_spectroscopy

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Re: Optics B/C

Postby Cloudia » Sat Dec 10, 2016 12:42 am

Thank you so much for your opinions, chalker! It's very reassuring to read that this material wasn't all meant to be covered. I'll expand our coverage of the borderline topics to be safe. Once again, I really appreciate that you've taken the time to help.

Superpenguin, I've sent you a private message with a bit of help.

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Re: Optics B/C

Postby Tom_MS » Sun Dec 25, 2016 12:37 pm

Cloudia wrote:Hello :)

While I was expecting that my students would struggle with the state/national level theory (lasers, multiple lenses, etc) that the Cornell Invitational is known for, there were questions in which I can't see how they fit within any of this year's optics topics. Alternatively, is it common to see more topics thrown than expected?



I'm currently a student, but I'll give you my take. The Cornell invitational is known for writing odd tests in some events, so I'm sorry to say I wouldn't base your studying off of the experience there.
To reference this year's rules, "Optical Absorption Spectra: Film, chemicals, dyes" could be interpreted as analysis of energy levels as well as analysis of spectra. This leads to a need for understanding the energy and characteristics of photons as well as methods such as diffraction which can produce spectral lines.
Redshift was on previous years' rules I believe, but not this year. In this respect, Cornell seems to have simply failed at following the rules.


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