Optics B/C

[jkang]

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.

I'm a grad and I've written/proctored various tests at different levels of tournaments, so here's my take on it. While some subjects might be outside of the defined area, I think that one of the most important part of the rules is in 4.c.: "The competition must consist of at least two questions from each of the following areas". Now the way I interpret this line may be different from how others do, but when I write tests the first thing I generally do is make sure that I meet this quota. However beyond these 20 questions, I generally add questions that are not listed in the provided topics (for example, wave optics and some astronomy-related things) that I think are still important to know for the overall subject of optics. This doesn't go against the rules at all as far as I can see, as I am meeting the 20 question requirement, but just adding some new topics/questions of my own on top of that. Thus if I was currently competing in Optics, I wouldn't limit myself to knowledge of just the topics listed, but try to get as much breadth as possible in the subject, as other test-writers could always think the same way I do. Plus that's representative of the spirit of Science Olympiad - not just limiting knowledge to content that will be presented on a test, but to have kids explore a subject beyond what schools/classes regularly teach as well as diving into the subject as much as they can/want.

[Tom_MS]

True. Some rules have different wording but with optics you're right.

[Fluorine]

Can someone check me back on this problem its a Doppler Shift one?

"A spaceship is moving away from an asteroid at a relative velocity of 2.8481 x 10^8 m/s. The spaceship sends a signal with a frequency of 5 x 10^6 Hz to a base located on the asteroid. What is the frequency of the signal measured by the base?"

I keep getting 2.56 x 10^6 Hz but the test key says the answer is 3.1225 x 10^7 Hz.

[John Richardsim]

Can someone check me back on this problem its a Doppler Shift one?

"A spaceship is moving away from an asteroid at a relative velocity of 2.8481 x 10^8 m/s. The spaceship sends a signal with a frequency of 5 x 10^6 Hz to a base located on the asteroid. What is the frequency of the signal measured by the base?"

I keep getting 2.56 x 10^6 Hz but the test key says the answer is 3.1225 x 10^7 Hz.

I jammed those numbers into an online doppler shift calculator and got your answer. Couldn't seem to figure out how to get their answer.

[jkang]

I keep getting 2.56 x 10^6 Hz but the test key says the answer is 3.1225 x 10^7 Hz.

Using hyperphysics and wolframalpha, I got 3.12*10^7 Hz if the spaceship moves towards the asteroid, rather than away from it - this follows common sense, as redshifting would lower frequency, whereas blueshifting would increase it. Looks like your proctor either misworded the question, or applied the wrong equation in his/her calculations of answers.

[whyiamafool]

Hello,

My team recently went to an invitational and found out that the TP (target point) was off 5 cm from the center line from that particular invitational. The team reviewed the rules once again and it says that event supervisors select a TP that is the same for all teams.

Does this mean that event supervisors can select a TP anywhere along the Target Wall?

Thanks.

[Adi1008]

Hello,

My team recently went to an invitational and found out that the TP (target point) was off 5 cm from the center line from that particular invitational. The team reviewed the rules once again and it says that event supervisors select a TP that is the same for all teams.

Does this mean that event supervisors can select a TP anywhere along the Target Wall?

Thanks.

Yeah, it can be anywhere along the back wall

[jonboyage]

Hello,

My team recently went to an invitational and found out that the TP (target point) was off 5 cm from the center line from that particular invitational. The team reviewed the rules once again and it says that event supervisors select a TP that is the same for all teams.

Does this mean that event supervisors can select a TP anywhere along the Target Wall?

Thanks.

Yes, the proctor can make the target anywhere along the target wall. So far, every invitational I have been to this year has had the target off-center. The farthest I've seen so far is 9cm off-center

[chalker]

Hello,

My team recently went to an invitational and found out that the TP (target point) was off 5 cm from the center line from that particular invitational. The team reviewed the rules once again and it says that event supervisors select a TP that is the same for all teams.

Does this mean that event supervisors can select a TP anywhere along the Target Wall?

Thanks.

Read rule 3.f. very carefully. It says one of the marks is the TP, It does NOT say a particular mark is the TP.

[egbertghost]

Can someone check me back on this problem its a Doppler Shift one?

"A spaceship is moving away from an asteroid at a relative velocity of 2.8481 x 10^8 m/s. The spaceship sends a signal with a frequency of 5 x 10^6 Hz to a base located on the asteroid. What is the frequency of the signal measured by the base?"

I keep getting 2.56 x 10^6 Hz but the test key says the answer is 3.1225 x 10^7 Hz.

I asked my cousin (an Astronomy Harvard professor) said to use the Red Doppler Shift formula, and then I got the same answer as you. The test writer probably did something wrong lol. Good luck!