## Search found 118 matches

April 5th, 2017, 6:30 pm
Forum: 2017 Question Marathons
Topic: Optics B/C
Replies: 127
Views: 12185

### Re: Optics B/C

Okay. After thinking a while, I think I have some idea.|The first signal S to arrive at that point x produces the smallest relaxation time of any frequency of the light. As frequency increases to this frequency, the relaxation time of the dielectric keeps decreasing and thus the signal propagates f...
April 4th, 2017, 5:57 pm
Forum: 2017 Lab Events
Topic: Optics B/C
Replies: 190
Views: 28959

### Re: Optics B/C

4.d.xii. The word "measurement" is used. Does this suggest to you that there might be laboratory work in addition to the box? I admittedly haven't looked closely at the S/N topics until this month. If I was writing for states/nats, I'd print a figure and either give a scale or make it to scale, the...
April 3rd, 2017, 7:58 pm
Forum: 2017 Question Marathons
Topic: Optics B/C
Replies: 127
Views: 12185

### Re: Optics B/C

Is this just simply...|By definition of the index of refraciton, n=c/v, where v is the speed of the electromagnetic radiation in the dielectric medium. Therefore, wouldn't s, the speed of the signal, just be c/n? Surprisingly and yet unsurprisingly, this is false. I'd recommend thinking more about ...
April 3rd, 2017, 4:16 pm
Forum: 2017 Question Marathons
Topic: Optics B/C
Replies: 127
Views: 12185

### Re: Optics B/C

Here's an interesting question from my graduate course. Suppose electromagnetic radiation propagates though a neutral dielectric in a region of normal dispersion. The medium has a refractive index n . Let s be the signal that first arrives at point x within the medium. At what velocity does s propag...
April 3rd, 2017, 4:06 pm
Forum: 2017 Lab Events
Topic: Optics B/C
Replies: 190
Views: 28959

### Re: Optics B/C

On the contrary, I would argue that being able to do these problems without your calculator is a useful skill and should be even faster than typing it into your calculator (especially if you have a bunch of trig that you have to locate in the menus) Tbh by the time I reached senior year (I got my 8...
April 3rd, 2017, 9:05 am
Forum: 2017 Question Marathons
Topic: Optics B/C
Replies: 127
Views: 12185

### Re: Optics B/C

Polarized light of intensity I strikes a rotating polarizing film whose angle is given by arcsin(1/t) where t is time in seconds. At one time does exactly 25% of the initial intensity of the polarized light get through the film? No one's tried in a while, so let me.|Malus' law states I = I0cos(x). ...
March 29th, 2017, 12:50 pm
Forum: 2017 Lab Events
Topic: Optics B/C
Replies: 190
Views: 28959

### Re: Optics B/C

However, more attempts to isolate x were unsuccessful. If you can, invest in a calculator like the TI-89. Perfectly allowed by the rules, and has an algebra solver in it. In something like SciO you really shouldn't have the time to do this by hand, this saves so much time (and is applicable in many...
March 25th, 2017, 10:08 pm
Forum: 2017 Invitationals, Regionals, and States
Topic: Texas 2017
Replies: 129
Views: 20732

### Re: Texas 2017

Results for the UT Austin regional are now available for Division B and Division C.
March 25th, 2017, 8:01 pm
Forum: 2017 Lab Events
Topic: Optics B/C
Replies: 190
Views: 28959

### Re: Optics B/C

With the UT Regional now over, here are my test and key for the tournament. I included explanations for each of my answers in the key this time, so hopefully that will help. Topics are a bit heavy on waves so unlikely to be seen at states/nats, but wave optics >> geometric optics
March 14th, 2017, 10:43 pm
Forum: 2017 Lab Events
Topic: Optics B/C
Replies: 190
Views: 28959

### Re: Optics B/C

Hi guys, Can someone explain how to solve this problem? It was on the question marathon (page 3 or 4 I think, kenniky's problem on angle of deviation in prisms) Thanks! Question: In the prism below, α is 35° and θ is 19°. The prism has index of refraction 1.45 and is in a vacuum What is the deviati...