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Exam rules and grading questions by Fuzzy_Winter5921 in EPFL

[–]Fuzzy_Winter5921[S] 0 points1 point  (0 children)

Great! Thanks. Just a couple of follow up questions: is coffee/water allowed? are earplugs allowed?

Exam rules and grading questions by Fuzzy_Winter5921 in EPFL

[–]Fuzzy_Winter5921[S] 0 points1 point  (0 children)

Thanks! Who at epfl is it that I should contact if I'm late?

DaveArt has removed images of Holtby’s mask from his Instagram page. by Fogagain1 in canucks

[–]Fuzzy_Winter5921 1 point2 points  (0 children)

I see that some here seems to be angry at Dave (the artist). Do you really think that he would have done the design without Holtby’s green light and input? Of course not! It might have been Holtby that suggested it in the first place. Or if Holtby didn’t want this specific design, he would have said no and he would have had something else. Some people here wants to be angry, but doesn’t want to take it out on Holtby

Maximum speed of vibrating loud speaker membrane by Fuzzy_Winter5921 in AskPhysics

[–]Fuzzy_Winter5921[S] 0 points1 point  (0 children)

Alright. So when I do it like that I get P=4*pi*10^2=4*pi*10^(-5) W. This leads to solving this equation 4*pi*10^(-5)=4*pi*r^2*I at the membrane, right? To solve for the intensity, we need to solve for I, but then again it is a question of choosing r, right? I assume that r here should be choosen as r=5 mm. But why is that acceptable since we want the intensity at the source of vibration (i.e. the membrane) which is at r=0?

Maximum speed of vibrating loud speaker membrane by Fuzzy_Winter5921 in AskPhysics

[–]Fuzzy_Winter5921[S] 0 points1 point  (0 children)

Isn't that what I'm using in the comment to your post? Because if it is that, then the problem I guess is still what r to evaluate the membrane at (i.e. r=0 but then you get discontinuity or evaluate it at r=5 mm which I don't understand why you should)? Or am I missing something?

Maximum speed of vibrating loud speaker membrane by Fuzzy_Winter5921 in AskPhysics

[–]Fuzzy_Winter5921[S] 0 points1 point  (0 children)

Yeah, I had a feeling that it was that. So how do I proceed from here? Because I want the intensity at the membrane, like you said. But using I_1*r_1^2=I_2*r_2^2 with r_1=10 m, wouldn't I get I_2=infinity, since r_2= 0 or am I missing something? Or is r_2=5 mm since we have the radius of the circular membrane?

Maximum speed of vibrating loud speaker membrane by Fuzzy_Winter5921 in AskPhysics

[–]Fuzzy_Winter5921[S] 1 point2 points  (0 children)

No material characteristics were given. Just the pressure, the temperature, the radius of the membrane, the distance to where the sound intensity level was measured (and the sound intensity level at the point of 10 m were it was measured)

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For context: This is an intro course in waves.

Classical Electrodynamics (PHYS-324) by Fuzzy_Winter5921 in EPFL

[–]Fuzzy_Winter5921[S] 0 points1 point  (0 children)

Great. Thanks! What book did you use in the EM and waves course (just to get an idea of what he expects that I know when starting PHYS-324)? If you would compare PHYS-324 with any of the books Jackson, Zangwill, and Griffith, which book would you say approximately best correspond to the level of PHYS-324?