Optics B/C

[cngu23]

I have been through the test exchange for this year, and in the Camas Invitational Test, i think, there was a question about magnetic field? or something similar to that, not mentioned in the rules. Should we prepare for those types of questions?

It is somewhat connected to electromagnetic waves, but not directly stated within the rules.

[Schrodingerscat]

I have been through the test exchange for this year, and in the Camas Invitational Test, i think, there was a question about magnetic field? or something similar to that, not mentioned in the rules. Should we prepare for those types of questions?

It is somewhat connected to electromagnetic waves, but not directly stated within the rules.

It would not be a bad idea to have a basic understanding of how magnetism is involved with optics, but I would not consider a critical topic to understand as it is not specifically mentioned in the rules.

[cngu23]

So how much information are you guys putting on the parts of the eye? I've been through some past tests and it gets very specific.

[Infinity Flat]

I have been through the test exchange for this year, and in the Camas Invitational Test, i think, there was a question about magnetic field? or something similar to that, not mentioned in the rules. Should we prepare for those types of questions?

It is somewhat connected to electromagnetic waves, but not directly stated within the rules.

This is the question:

3. Suppose that the electric field of an electromagnetic wave decreases in magnitude. Does the
magnetic field increase, decrease, or remain the same? (1 point)

The correct answer was "decrease."

Light is electromagnetic radiation. EMR has both electric and magnetic field components, which oscillate in phase perpendicular to each other and perpendicular to the direction of energy propagation (the direction the photon is moving.) The oscillation of the electric component leads to an oscillation in the magnetic field, and vice versa. This makes the electromagnetic wave self-propagating, meaning that it does not need some substance in order to travel (compared to sound waves or earthquakes.) When the electric part of the light changes, the magnetic part of the light changes in exactly the same way. So if you decrease how much energy (the amplitude) the electric part has, the amount of energy the magnetic part has will decrease as well.

tl;dr Light is electromagnetic radiation, which has electric and magnetic components, which always have the same amplitude as each other.

I selected this question from a high school physics textbook. I'd say about 1/2 - 2/3 of people answered this question correctly. At this tournament, we had three state champion teams (WA, OR, NoCal), and so I wrote a somewhat more difficult test than what you might see at another invitational or a regional competition.

[Pauly_Rocks]

Anyone have ideas on laser shoot templates? My partner and I were trying to make some templates to use the other day, and they didn't work that well. Any ideas?

[Infinity Flat]

Anyone have ideas on laser shoot templates? My partner and I were trying to make some templates to use the other day, and they didn't work that well. Any ideas?

I'd try working out a general design on paper first, and then using the laser and mirrors to create a more precise one.
For B division, you'll probably be best off making three templates: one for when the block is very close to the laser, another for when the block is very close to the target, and a third for when the block is closer to the middle of the box. You want that third one to be fairly flexible, as you'll be using it in the most situations. The less paper you use with the template, the more situations you can use it. For the central template, I will say there is definitely a "solution" that will get you all of the points every time. The other two possibilities I'm unsure on, though.

[foreverphysics]

Anyone have ideas on laser shoot templates? My partner and I were trying to make some templates to use the other day, and they didn't work that well. Any ideas?

You can use hangfromthefloor's template maker. Assuming it still works.
http://ophir.li/scioly/events/optics/?u ... mpaign=wop

[SciBomb97]

Although I am still trying to figure out that part myself, my brainstorming (powerful storms in my cerebellumish area) has come up with three pieces of advice:
>Make the template rigid, or out or rigid paper material (so that the angle measurements on it won't be messed up due to template problems).
>Make the templates as square as possible (completely geometric), so that multiple templates can be placed side by side and the decreases in accuracy by using multiple templates is reduced.
>Make the templates so that stacking side by side is possible (kind of how you would put boxes side by side, so that the sides are parallel when you place them so).

[Infinity Flat]

Anyone have ideas on laser shoot templates? My partner and I were trying to make some templates to use the other day, and they didn't work that well. Any ideas?

You can use hangfromthefloor's template maker. Assuming it still works.
http://ophir.li/scioly/events/optics/?u ... mpaign=wop

Only if you're planning on only using two of the mirrors.

[cngu23]

What are some good sources for information on telescopes, cameras, and microscopes?
Right now, I'm using the Giancoli physics textbook and wikipedia.