Post by: awesome2damax on November 10, 2010, 01:37:33 pm
Post by: Johnvay on November 10, 2010, 01:41:41 pm
Post by: Munkea on November 10, 2010, 01:43:42 pm
Post by: Sheen on November 10, 2010, 01:48:50 pm
and that X-ray Q,, fck me... i think i lost all 5 points of that question
Post by: Whatlol on November 10, 2010, 01:49:01 pm
what did you guys do for the circuit.. i got thrown off
anyone want me to attempt solutions? i got an exam
Post by: Munkea on November 10, 2010, 01:51:47 pm
woops didnt see there was already a thread... )=
what did you guys do for the circuit.. i got thrown off
anyone want me to attempt solutions? i got an exam
You had to wire up the circuit in series to give an overall resistance of 96 ohms.
Post by: curious111 on November 10, 2010, 01:51:55 pm
Anyone remember a number like 24000 for the photon energy question?
Post by: Sheen on November 10, 2010, 01:52:53 pm
woops didnt see there was already a thread... )=-3- 48+48=96ohms?
what did you guys do for the circuit.. i got thrown off
so its a circuit in series..?
im not sure
Post by: Whatlol on November 10, 2010, 01:53:30 pm
Post by: Munkea on November 10, 2010, 01:54:41 pm
it was in series but i didnt know how to draw it )=
Just a diagonal line connecting the two open points
Post by: Whatlol on November 10, 2010, 01:56:50 pm
it was in series but i didnt know how to draw it )=
Just a diagonal line connecting the two open points
damn there goes two marks.
Post by: Whatlol on November 10, 2010, 01:57:56 pm
Post by: zackyjack on November 10, 2010, 01:58:24 pm
woops didnt see there was already a thread... )=-3- 48+48=96ohms?
what did you guys do for the circuit.. i got thrown off
so its a circuit in series..?
im not sure
I said that they were in series, so 600W
Post by: zackyjack on November 10, 2010, 01:58:42 pm
What was the physical law you use to construct the graph in question 8
I said Faraday's Law.
Post by: jayna on November 10, 2010, 01:59:30 pm
I said lenz's?What was the physical law you use to construct the graph in question 8
I said Faraday's Law.
Post by: Whatlol on November 10, 2010, 01:59:35 pm
What was the physical law you use to construct the graph in question 8
I said Faraday's Law.
I was thinking conservation of energy... )=
Post by: zackyjack on November 10, 2010, 02:00:02 pm
woops didnt see there was already a thread... )=Whatlol, I'd love to see the transmission questions worked out, after they make the final power 4W and you have to work back to find the voltage.
what did you guys do for the circuit.. i got thrown off
anyone want me to attempt solutions? i got an exam
Post by: byr0003 on November 10, 2010, 02:00:25 pm
Post by: Sheen on November 10, 2010, 02:00:30 pm
fck i wrote some random... like Lenz's LawWhat was the physical law you use to construct the graph in question 8
I said Faraday's Law.
Post by: Xavier1234 on November 10, 2010, 02:00:50 pm
Post by: jayna on November 10, 2010, 02:01:44 pm
Post by: curious111 on November 10, 2010, 02:02:43 pm
Post by: Galvanic Cell on November 10, 2010, 02:03:10 pm
Post by: John President on November 10, 2010, 02:03:25 pm
Post by: eOkee on November 10, 2010, 02:05:45 pm
Post by: Linkage1992 on November 10, 2010, 02:10:39 pm
For this, you would have to state Lenzs law.
Post by: Xavier1234 on November 10, 2010, 02:12:24 pm
Your graph had to start of negative and then go to positive.
For this, you would have to state Lenzs law.
itute helper says faradays. hmm i went with lenz..
Post by: rubiks on November 10, 2010, 02:13:58 pm
Post by: Linkage1992 on November 10, 2010, 02:15:18 pm
Post by: John President on November 10, 2010, 02:16:56 pm
I'm looking pretty good with the iTute answers so far...
Post by: kenhung123 on November 10, 2010, 02:24:42 pm
Post by: j43768 on November 10, 2010, 02:26:59 pm
and from wikipedia - Faraday's law of induction indicates that the induced electromotive force (emf) and the change in flux have opposite signs, and it also gives the direction of the induced (emf) and current resulting from electromagnetic induction.
so i said faradays'
Post by: physics on November 10, 2010, 02:28:59 pm
Post by: Xavier1234 on November 10, 2010, 02:31:01 pm
for the very very first question is it n on the left and s on the right :( ..thats what i got
is this the force question?
Post by: physics on November 10, 2010, 02:31:48 pm
Post by: coletrain on November 10, 2010, 02:32:19 pm
Post by: SixWinged on November 10, 2010, 02:34:36 pm
Post by: Greggler on November 10, 2010, 02:36:17 pm
faraday is the law that emf=change in flux/change in time
im pretty sure it could only be faradays
Apart from that i think i lost about 2 marks in each section. Couldnt do the X-Ray one, kept getting 600 even though i gound the wavelength and momemtun and stuff ><
Post by: supernatural on November 10, 2010, 02:37:04 pm
it's gotta be lenz's law. negative gradient of flux changeyeh thats faradays law
Post by: physics on November 10, 2010, 02:37:43 pm
Post by: physics on November 10, 2010, 02:38:16 pm
LENZ has negative symbol
O_O thats what VU lecture dude told me~~~
Post by: m@tty on November 10, 2010, 02:39:15 pm
Post by: SixWinged on November 10, 2010, 02:39:27 pm
when u drew the graph ..if u did the negative diff of it then its lenzs.
I maintain that you could acheive a negative EMF by wiring the opposite terminals of the volt meter up, so technically VCAA should give a positive or negative EMF correct. Using this logic Lenz's law isn't relevant to the graph.
Post by: SixWinged on November 10, 2010, 02:40:25 pm
FARADAYS is without negaitve symbol
LENZ has negative symbol
O_O thats what VU lecture dude told me~~~
Lenz's IS the negative symbol, or more correctly it's the sign/direction of the emf where Faraday's is the magnitude.
EDIT: Sorry, didn't mean to double post.
Post by: garliczombie on November 10, 2010, 02:40:47 pm
it was in series but i didnt know how to draw it )=
LMAO same. I just wrote down its in series. hope i get a mark for it
Post by: Greggler on November 10, 2010, 02:41:55 pm
Post by: physics on November 10, 2010, 02:44:18 pm
Post by: garliczombie on November 10, 2010, 02:44:36 pm
for the very very first question is it n on the left and s on the right :( ..thats what i got
yea im 95% sure you are correct. itute may have made a mistake
Post by: Blakhitman on November 10, 2010, 02:45:11 pm
Post by: m@tty on November 10, 2010, 02:45:28 pm
for the very very first question is it n on the left and s on the right :( ..thats what i got
yea im 95% sure you are correct. itute may have made a mistake
Yep, you're right physics. The field lines go from the left around to the right, I'm certain.
Post by: Blakhitman on November 10, 2010, 02:45:49 pm
for the very very first question is it n on the left and s on the right :( ..thats what i got
yea im 95% sure you are correct. itute may have made a mistake
So the arrows go through the solenoid from right to left, don't see how itute is wrong.
Post by: SixWinged on November 10, 2010, 02:45:55 pm
I did positive voltage at the start, then into a negative voltage? would i get a single mark for this atleast?
Personally I believe you're OK since no indication is given of which terminal of the voltage meter is hooked up to which wire, but don't be surprised if you lost 1 mark by VCAA marking standards.
Post by: Xavier1234 on November 10, 2010, 02:46:12 pm
QUESTION! WAS THERE ANY FLUX IN QUESTION 2... MY HAND TOLD ME THERE WAS SO I ASSUME MY HAND WASNT LYING BUT ITUTE SAYS THAT IT WAS :"(
the effective area of the plane was parallel to the mag.field. flux=field(area sintheta) = BAsin0 = OWb
Post by: m@tty on November 10, 2010, 02:47:14 pm
It's faraday's for sure.
Yeah it was Faraday's mostly. BUT you also had to use Lenz's law to get an emf opposite in direction for the second part. SO I wrote "Faraday's law (and Lenz's)"..
Post by: Xavier1234 on November 10, 2010, 02:48:53 pm
the first first question ::( the one about drawing the lines.
oh yeah it was Left-North
Post by: physics on November 10, 2010, 02:49:49 pm
NOOOOOOOOOOOOOO! :( (as in agreeing with you sorta no) damnnnnnnnndmamandndndndndQUESTION! WAS THERE ANY FLUX IN QUESTION 2... MY HAND TOLD ME THERE WAS SO I ASSUME MY HAND WASNT LYING BUT ITUTE SAYS THAT IT WAS :"(
the effective area of the plane was parallel to the mag.field. flux=field(area sintheta) = BAsin0 = OWb
Post by: nehcrow on November 10, 2010, 02:52:21 pm
Post by: Blakhitman on November 10, 2010, 02:53:58 pm
It's faraday's for sure.
Yeah it was Faraday's mostly. BUT you also had to use Lenz's law to get an emf opposite in direction for the second part. SO I wrote "Faraday's law (and Lenz's)"..
The negative part was from the negative in the formula, basically emf=negative gradient of flux(field) Vs time graph.
Gradient was positive for the first part and negative for the second, so the emf was negative, then positive...
Post by: m@tty on November 10, 2010, 02:57:50 pm
And I don't think it necessarily had to be negative then positive.. You don't know which way the voltmeter was connected.. So it could read positive then negative.
Post by: Blakhitman on November 10, 2010, 03:04:12 pm
Faraday's law has no negative in it..
And I don't think it necessarily had to be negative then positive.. You don't know which way the voltmeter was connected.. So it could read positive then negative.
Yea the order didn't necessarily matter...
I guess you could be right...
Post by: m@tty on November 10, 2010, 03:11:48 pm
Quote
The induced electromotive force (emf) in any closed circuit is equal to the time rate of change of the magnetic flux through the circuit.
No negative.. I always thought that Faraday's law only gave the magnitude.
Post by: Blakhitman on November 10, 2010, 03:20:23 pm
Even if I'm right, you put both so hopefully you get a mark. If you're right then I get 0 haha
Post by: m@tty on November 10, 2010, 03:33:01 pm
I reckon a bastard examiner won't see what I meant and would penalise me for what he perceives as hedging my bets xD
Post by: Blakhitman on November 10, 2010, 03:34:50 pm
What?.. Why does the equation not align with the explanation.. No matter.. Argh, I trusted the MGS guy at VU. He said Lenz's law is Faraday's with the negative >.<
I reckon a bastard examiner won't see what I meant and would penalise me for what he perceives as hedging my bets xD
You'll be fine, even if you lose it, 87 will most definitely still be an A+!!
Post by: Zoffle on November 10, 2010, 03:35:38 pm
Post by: qshyrn on November 10, 2010, 04:53:06 pm
he basically told us whats on the exam (he said that there was gonna be a 50% chance the xray/electron q was gonna on it and then told us about that diffraction pattern/similar wavelength) , and also a bunch of other stuff which i cant remember...
Post by: kyzoo on November 10, 2010, 04:59:22 pm
What?.. Why does the equation not align with the explanation.. No matter.. Argh, I trusted the MGS guy at VU. He said Lenz's law is Faraday's with the negative >.<
I reckon a bastard examiner won't see what I meant and would penalise me for what he perceives as hedging my bets xD
MGS guy?
Post by: physics on November 10, 2010, 05:01:44 pm
Post by: Whatlol on November 10, 2010, 05:02:44 pm
DID ANYONE SAY OBSERVATION1 :( its wrong wrong wrong >: (
i think its OB 2 , itute changed from 1 to 3. so who knows
Post by: waack on November 10, 2010, 05:03:20 pm
Post by: Blakhitman on November 10, 2010, 05:03:30 pm
Post by: waack on November 10, 2010, 05:04:39 pm
Post by: m@tty on November 10, 2010, 05:20:33 pm
What?.. Why does the equation not align with the explanation.. No matter.. Argh, I trusted the MGS guy at VU. He said Lenz's law is Faraday's with the negative >.<
I reckon a bastard examiner won't see what I meant and would penalise me for what he perceives as hedging my bets xD
MGS guy?
Um Geoff Davies ran the free VU lecture.
Post by: kyzoo on November 10, 2010, 05:23:03 pm
What?.. Why does the equation not align with the explanation.. No matter.. Argh, I trusted the MGS guy at VU. He said Lenz's law is Faraday's with the negative >.<
I reckon a bastard examiner won't see what I meant and would penalise me for what he perceives as hedging my bets xD
MGS guy?
Um Geoff Davies ran the free VU lecture.
0.o he's my physics teacher, he's epically pro =/
I think he also told our calss in like Term 3 that Lenz's law is faraday's law with engative sign on it =/ then he told us that lenz's law = direction and faraday's law = magnitude later on.
Post by: d-ea-6 on November 10, 2010, 05:23:15 pm
What?.. Why does the equation not align with the explanation.. No matter.. Argh, I trusted the MGS guy at VU. He said Lenz's law is Faraday's with the negative >.<
I reckon a bastard examiner won't see what I meant and would penalise me for what he perceives as hedging my bets xD
MGS guy?
Um Geoff Davies ran the free VU lecture.
Yeah, he teaches at Melbourne Grammar School (MGS) :P
It's observation 2 for sure hands down, will bet my left nut(ella) on it.
I sure hope you're right because I put down Observation 2 as well :D
Post by: tolybangn on November 10, 2010, 05:24:05 pm
Im almost certain that as I was reading it I knew that neither answer was a full explanation, and that both answers fit in accordance with the question (I believe it was along the lines of "what law was used to arrive at this graph" or something).
They really need to give the mark for either, in my opinion; the only way they could justify that one answer was correct is by using the "we are the VCAA and our interpretation is the only interpretation" argument.
(unrelated, but SERIOUSLY, last question of the GAT, asking us what ART OBJECTIVELY CONVEYS. They must think they are God or something.)
Post by: Blakhitman on November 10, 2010, 05:24:30 pm
What?.. Why does the equation not align with the explanation.. No matter.. Argh, I trusted the MGS guy at VU. He said Lenz's law is Faraday's with the negative >.<
I reckon a bastard examiner won't see what I meant and would penalise me for what he perceives as hedging my bets xD
MGS guy?
Um Geoff Davies ran the free VU lecture.
lol he ran the TSFX mid-year...got dropped ey :buck2:
NO I'M OBVIOUSLY KIDDING derrrrr
Post by: m@tty on November 10, 2010, 05:28:40 pm
Post by: Whatlol on November 10, 2010, 05:30:48 pm
can someone who has the exam please type up the verbatim instruction of the Faraday/Lenz law question??
Im almost certain that as I was reading it I knew that neither answer was a full explanation, and that both answers fit in accordance with the question (I believe it was along the lines of "what law was used to arrive at this graph" or something).
They really need to give the mark for either, in my opinion; the only way they could justify that one answer was correct is by using the "we are the VCAA and our interpretation is the only interpretation" argument.
(unrelated, but SERIOUSLY, last question of the GAT, asking us what ART OBJECTIVELY CONVEYS. They must think they are God or something.)
Identify the physical law you used for constructing your graph
Post by: a.zirek on November 10, 2010, 06:40:10 pm
it's gotta be lenz's law. negative gradient of flux change
Ermm... Negative gradient of flux change is Faraday's Law.
Lenz's law is about induced current
Post by: kakar0t on November 10, 2010, 06:41:26 pm
it's gotta be lenz's law. negative gradient of flux change
Ermm... Negative gradient of flux change is Faraday's Law.
Lenz's law is about induced current
I thought the physical law was the law of electromagnetic induction... but i put down faradays
Post by: m@tty on November 10, 2010, 06:47:33 pm
Anyway, the point I'm getting at is that this guy said that with the negative it's Lenz's and without it it's Faraday's..
Post by: a.zirek on November 10, 2010, 06:48:19 pm
'Compare and contrast Faraday's law and Lenz's Law.'
The answer:
'Faraday's Law gives the magnitude of the induced current, while Lenz's law gives the direction.'
Post by: Xavier1234 on November 10, 2010, 06:55:01 pm
It's my understanding that the negative was not in the emf formula until Lenz put it there. Geoff Davies, the MGS guy that I was talking about earlier, said that Lenz made a link between LeChatelier's principle and the induced current - he reasoned that systems oppose change.. So the direction of the induced current must be such that it opposes the change. Davies said he chucked a negative sign out front of Faraday's emf formula, and it then became Lenz's law, rather than Faraday's...
Anyway, the point I'm getting at is that this guy said that with the negative it's Lenz's and without it it's Faraday's..
geoff davies? he's my teacher. lolz
Post by: Xavier1234 on November 10, 2010, 06:57:53 pm
It's my understanding that the negative was not in the emf formula until Lenz put it there. Geoff Davies, the MGS guy that I was talking about earlier, said that Lenz made a link between LeChatelier's principle and the induced current - he reasoned that systems oppose change.. So the direction of the induced current must be such that it opposes the change. Davies said he chucked a negative sign out front of Faraday's emf formula, and it then became Lenz's law, rather than Faraday's...
Anyway, the point I'm getting at is that this guy said that with the negative it's Lenz's and without it it's Faraday's..
yeah he always bags lenz guy for apparently "just putting a negative sign" in faraday's eq. and end up winning a nobel prize himself. i dont remember him saying that faraday and lenz are the same though
Post by: minimum on November 10, 2010, 06:58:33 pm
What?.. Why does the equation not align with the explanation.. No matter.. Argh, I trusted the MGS guy at VU. He said Lenz's law is Faraday's with the negative >.<
I reckon a bastard examiner won't see what I meant and would penalise me for what he perceives as hedging my bets xD
MGS guy?
Um Geoff Davies ran the free VU lecture.
lol he ran the TSFX mid-year...got dropped ey :buck2:
NO I'M OBVIOUSLY KIDDING derrrrr
He took the end of the year Sound too ( if i remember right)
Post by: Xavier1234 on November 10, 2010, 07:01:01 pm
What?.. Why does the equation not align with the explanation.. No matter.. Argh, I trusted the MGS guy at VU. He said Lenz's law is Faraday's with the negative >.<
I reckon a bastard examiner won't see what I meant and would penalise me for what he perceives as hedging my bets xD
MGS guy?
Um Geoff Davies ran the free VU lecture.
lol he ran the TSFX mid-year...got dropped ey :buck2:
NO I'M OBVIOUSLY KIDDING derrrrr
He took the end of the year Sound too ( if i remember right)
nah it was anthony novak. the guy who always delivered a 15minute hate speech against vcaa before lectures. wouldnt blame him one bit.
Post by: tolybangn on November 10, 2010, 08:15:51 pm
can someone who has the exam please type up the verbatim instruction of the Faraday/Lenz law question??
...
Identify the physical law you used for constructing your graph
Thanks; I think it proves my point.
I used both laws to construct my graph; I used Faraday's law to know the voltage was proportional to the change in flux, and I used Lenz's law to know that the line segments from 0 to 1 and from 2 to 4 (iirc) must be on opposite sides of the x axis (ie. one -ve, one +ve). Without both I could not have constructed my graph correctly.
The VCAA would be completely ignorant to even begin to argue that one answer is wrong.
Post by: theuncle on November 10, 2010, 08:56:26 pm
I thought it was in parallel, as this halves the effective resistance and hence gives a power of 600W which was half of the original 1200W element.
Post by: Whatlol on November 10, 2010, 08:58:14 pm
You guys are saying the circuit was in series?
I thought it was in parallel, as this halves the effective resistance and hence gives a power of 600W which was half of the original 1200W element.
yea had to be in series. P = V^2/R
P = 240^2 / 96 = 600W
Post by: m@tty on November 10, 2010, 08:59:07 pm
You guys are saying the circuit was in series?
I thought it was in parallel, as this halves the effective resistance and hence gives a power of 600W which was half of the original 1200W element.
It was in series. Halving the resistance doubles the current and
You had to double the resistance, by putting the elements in series, which consequently halves the power. :)
Post by: minimum on November 22, 2010, 07:14:27 pm
What?.. Why does the equation not align with the explanation.. No matter.. Argh, I trusted the MGS guy at VU. He said Lenz's law is Faraday's with the negative >.<
I reckon a bastard examiner won't see what I meant and would penalise me for what he perceives as hedging my bets xD
MGS guy?
Um Geoff Davies ran the free VU lecture.
lol he ran the TSFX mid-year...got dropped ey :buck2:
NO I'M OBVIOUSLY KIDDING derrrrr
He took the end of the year Sound too ( if i remember right)
nah it was anthony novak. the guy who always delivered a 15minute hate speech against vcaa before lectures. wouldnt blame him one bit.
oh truee that! but maybe Light then! im sure he was in something :/ maybe im thinking midyear then .