Optics B/C

[John Richardsim]

Hellloooooooo,
For Div. B, is it necessary to know the percentage of reflection in a refractive problem? (in refraction part of the incident ray, part of it is reflected). Basically do we need to know the percentage that is reflected. (sorry if this is very confusing). I JUST NEED TO KNOW!!!!! ;) ;) ;) ;) ;) ;) ;)

If I'm not mistaken, the reflectance of a surface is calculated using the Fresnel equations, which would be rather tedious to use in a question. The only manner in which this sort of topic has been asked on a test that I've seen is the special cases of total internal reflection and Brewster's angle.

[keklord88]

Does anyone know if we're allowed to use other tools to measure the angle besides just a simple protractor? (eg. digital angle gauge)
And what about a tape measure instead of a clunky ruler?

[Jdoglloyd]

Does anyone know if we're allowed to use other tools to measure the angle besides just a simple protractor? (eg. digital angle gauge)
And what about a tape measure instead of a clunky ruler?

Wouldn't a tape measure be clunkier? With the metal casing and all

[keklord88]

Does anyone know if we're allowed to use other tools to measure the angle besides just a simple protractor? (eg. digital angle gauge)
And what about a tape measure instead of a clunky ruler?

Wouldn't a tape measure be clunkier? With the metal casing and all

The tape can be bent so you would make a "L" shape with the tape measure so that the casing would be out of the way. This way you can measure in tight spaces that you otherwise coudn't with an inflexible ruler. Horrible drawing showing what I mean:

[Adi1008]

Does anyone know if we're allowed to use other tools to measure the angle besides just a simple protractor? (eg. digital angle gauge)
And what about a tape measure instead of a clunky ruler?

Wouldn't a tape measure be clunkier? With the metal casing and all

The tape can be bent so you would make a "L" shape with the tape measure so that the casing would be out of the way. This way you can measure in tight spaces that you otherwise coudn't with an inflexible ruler. Horrible drawing showing what I mean:

You could also just use smaller rulers

I think tape measures are allowed (rule 2.b) since it counts as "any measuring tool"

[keklord88]

Wouldn't a tape measure be clunkier? With the metal casing and all

The tape can be bent so you would make a "L" shape with the tape measure so that the casing would be out of the way. This way you can measure in tight spaces that you otherwise coudn't with an inflexible ruler. Horrible drawing showing what I mean:
You could also just use smaller rulers

I think tape measures are allowed (rule 2.b) since it counts as "any measuring tool"

Cool.
I guess the digital angle gauges could also be used since it's also a measuring tool.

[Jdoglloyd]

The tape can be bent so you would make a "L" shape with the tape measure so that the casing would be out of the way. This way you can measure in tight spaces that you otherwise coudn't with an inflexible ruler. Horrible drawing showing what I mean:
You could also just use smaller rulers

I think tape measures are allowed (rule 2.b) since it counts as "any measuring tool"

Cool.
I guess the digital angle gauges could also be used since it's also a measuring tool.

And yeah I mean those are gonna be the most accurate too

[jxxu20]

Hi all,

This is my first year doing Optics, and I'm not really sure on how the Event Supervisors will be running the event (I have NJ regionals @ UCC in less than 2 weeks). More specifically, I'm wondering -- based on your guys' experience -- how long/hard the tests are for Division B, and the topics that will be assessed. I know that the content assessed should align with the guidelines in the rules packet, but based on my limited experience, some of the material covered in tests are way harder than what I studied for (like some of the tests on the Test Exchange), while some tests are extremely easy. Moreover, how will the Event Supervisors be running the LSS? For example, how much time do we have to make calculations/place our mirrors down? I know that the rules state that "Participants must make all measurements ... within a 4-minute time period.", but in previous years, have Event Supervisors tweaked the time limit/constraints for the LSS setup?

Finally, I'm using a simple 45-degree mirror template with 4 mirrors (the template doesn't include reflecting off of a fifth mirror OR a barrier mirror, but using this template puts me on the safe side. However, the rules packet states "...15 points if the laser reflects off the barrier mirror." and says that each reflection off of a moveable mirror is worth 2 points -- so I'm basically sacrificing 17 pts off my total score even if I hit the target point spot-on). Based on your experience, what is the success rate for the laser actually being directed towards the target point, and what is the typical number of mirrors contestants use? Do contestants in Division B use the barrier mirror? (I know I'm putting out a weird question, but I want to see if I should stay with my 4-mirror template or change it based on others' performance.) Please note that this is a Division B tournament, not Division C, so we only have one barrier mirror.
Thanks for all of your help! I really appreciate it!

-- jxxu20

[WhatScience?]

Hi all,

This is my first year doing Optics, and I'm not really sure on how the Event Supervisors will be running the event (I have NJ regionals @ UCC in less than 2 weeks). More specifically, I'm wondering -- based on your guys' experience -- how long/hard the tests are for Division B, and the topics that will be assessed. I know that the content assessed should align with the guidelines in the rules packet, but based on my limited experience, some of the material covered in tests are way harder than what I studied for (like some of the tests on the Test Exchange), while some tests are extremely easy. Moreover, how will the Event Supervisors be running the LSS? For example, how much time do we have to make calculations/place our mirrors down? I know that the rules state that "Participants must make all measurements ... within a 4-minute time period.", but in previous years, have Event Supervisors tweaked the time limit/constraints for the LSS setup?

Finally, I'm using a simple 45-degree mirror template with 4 mirrors (the template doesn't include reflecting off of a fifth mirror OR a barrier mirror, but using this template puts me on the safe side. However, the rules packet states "...15 points if the laser reflects off the barrier mirror." and says that each reflection off of a moveable mirror is worth 2 points -- so I'm basically sacrificing 17 pts off my total score even if I hit the target point spot-on). Based on your experience, what is the success rate for the laser actually being directed towards the target point, and what is the typical number of mirrors contestants use? Do contestants in Division B use the barrier mirror? (I know I'm putting out a weird question, but I want to see if I should stay with my 4-mirror template or change it based on others' performance.) Please note that this is a Division B tournament, not Division C, so we only have one barrier mirror.
Thanks for all of your help! I really appreciate it!

-- jxxu20

Ayy my UCC people. I will be competing Optics B at UCC too. What school are you from? Will I be seeing you? I'm from HMS Anyway, for your question, take notes on the guidelines, take tests, and then for those tests whatever you don't know, study it and then add it to your binder. Rinse and repeat.

[jxxu20]

Thanks! Do you have other advice on the LSS portion of the event? What should I expect from the Event Supervisor? Will they have multiple LSS's so that multiple teams can compete at once?
Also, I'm from HMS, which is Heritage Middle School (not Hillsborough, which is where you're from). Heritage is relatively new to SO, as this is our second year in the Olympiad. We're from northern NJ but for some reason NJSO moved us to UCC -- not sure why that happened. Last year we went to the NJIT tournament.
As to whether I'll be seeing you, I don't think so. Heritage is team #9 whereas Hillsborough is team #10, and participating teams have been grouped into 2 sessions. Teams 1-9 will be competing together and teams 10-18 will be competing together.

Fun fact: Wirt -- director of NJSO -- used to be the HMS principal!