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Post your Physics questions here. (2 Viewers)

clementc

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don't think you need to give olympiad answers to these noobs
guys he lieeeeeeeees
this guy went to asian physics olympiad and was asked to go to international but turned it down =P
hello genius >=]
 

chevlr

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guys he lieeeeeeeees
this guy went to asian physics olympiad and was asked to go to international but turned it down =P
hello genius >=]
yehhh but this guy was coming first at ruse at phys, and apparently gives away ruse papers FOR FREE!!!! ladies one at a time please enough clementc for everyone :D
 

clementc

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Yeah, I came first, but I go to St Ruse IX Catholic school which is like ranked 500th, so yeah =\
If you want St Ruse IX papers anytime call me
But this guy is 2nd in Baulko and he has EVERY PAST PAPER from EVERYON SCHOOL dating back to 2000 with WORKED SOLUTIONS on CD that he gives away for FREE. MOB HIM
 
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chevlr

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Yeah, I came first, but I go to St Ruse IX Catholic school which is like ranked 500th, so yeah =\
If you want St Ruse IX papers anytime call me
But this guy goes to Baulko and he has EVERY PAST PAPER from EVERYON SCHOOL dating back to 2000 with WORKED SOLUTIONS on CD that he gives away for FREE. MOB HIM
lol i bet your school is filled with dumb azns who mistook the name :D. nahhh if you want past papers i think you should as sacredoblivion, apparently he is very willing to give them away.
 

clementc

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oh yeah isnt he like dux of sydney grammar? also offers free tutoring for little kiddies ;)
 

clementc

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Could you describe how you did it? It might have been just a calculator error or something =)
 

clementc

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Haha why are you still up =P
Um, so flux is like the number of field lines penetrating the plane of the coil. So naturally when the surface of it faces the B field, it's got the most number of field lines penetrating it. When the coil is edge on (like with one edge facing you), then there's zero field lines penetrating it, i.e. flux is zero. (they have an eqn for flux: )


Anyway, so at first, t=0, its got most number of field lines penetrating. i.e. flux is greatest. then when XY is closest to you, edge on, the flux is zero because no filed lines are passing thru that surface. when XY has rotated to the right instead, the flux is instead equal in magnitude but opposite in sign to when it just started at t=0. then it ends back at its starting place after another 90 degree rotation.

SO YAY A.

CAn't be C, because flux isn't zero to start with at t=0. also flux has a kind of direction (pedants might pick on me sayingthis, because flux is a dot product so technically has no direciton). but yeah flux going in from one side will have the opposite sign to flux going in from the other side, so direciton does kind of matter.
Sorry my typing/spelling has descending into a blabbering mess. too late at night lol tired and still have so much chemistry to learn =(
 
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Aclipse

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oh damn
I see where my mistake is


but would it be right to say that the "rate of change of magnetic flux" to be maximum at t=0?

And if the question asks for (delta) flux, does that have direction too or not?
 

clementc

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Haha it probably isn't right to say rate of change of flux () is a maximum at t=0. At t=0, !
Remember from maths that the rate of change is equal to the gradient at that instant, and at t=0, the gradient is just horizontal haha
It's magnitude would rather be at a maximum at t=1/4 and 3/4 of the way around (i.e. when the face XY is directly facing/away from us, edge on)

Kind of dodgily, if you think about when it's edge on, moving a tiny bit off edge on makes lots more field lines pass through it. But when its directly face on with the field, moving it a little off to one side doesn't make much difference.

What do you mean by when the question asks for ? Do you mean in Faraday's law, when you have to find ? I'm not sure, but I just normally take the absolute value (like if flux goes from 3 Wb to 1 Wb in 1 second, then I just chuck absolute signs around it and go errrr... xDD
 
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Aclipse

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lol i'm not sure anymore

when it comes up in the exam i'll just have to resort to good old gut instinct then
 

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