Post by: pinchies on November 12, 2008, 01:44:53 pm
-->http://vcenotes.com/forum/index.php/topic,7570.0.html
I think it was a little harder than last year on a few q's, but mostly easier. Longer too?
Lets begin... 8-)
Magnets & Stuff
--------------------
1. Use rh grip rule, current flowing anti-clockwise
X. Coil leaving Field:
change in flux = final flux - initial flux = zero - into page = out of page. According to lenz law, this change is opposed, hence field set up into page. Via rh grip rule, current flows clockwise, from (p/q I cant remember) to (p/q). Q-P (Clockwise) (unsure-> need mao or someone to confirm. :-\ )
X.Vrms = Vp-p ÷ 2 ÷root(2) (I cant do latex :-( )
8÷2÷root(2) = 2.8V
X Power of spotlight over fountain = 48W
X. Voltage over globe 9v
X. Current in circuit = (0.5Ω*2 + 3Ω÷2 = 2.5Ω therefore 12/2.5 =) 4.8A
X. Power = v^2/R = 40W
X. *V
X. Current at primary = 0.167A
X. 400 turns
Light & Matter & Stuff
------------------------
X. 0.0364nm
X. 97nm
X. h = 5x10^-15 evs
X. 3.03
X. 2.4ev
X. Arrow from n=4 (12.8) to n=2 (10.6) with head at 2
X. Jump from 12.8 -> 0 = max energy = max freq = min wavelength
Photonics & Stuff (thanks Hamtarofreak)
--------------------
1.D
2.B
3.C
4.C
5.C
6.B
7.B
8.C
9.C
10.A
11.C
12.C
13.A
Syncrotron & Stuff
---------------------
Sound & Stuff
-----------------
1.B
2.B
3.B
4.C
5.B
6.B
7.C (B?)
8.C
9.C (B?)
10.C
11.A (D?)
12.B (C,A?)
13.C (B,D?)
:-) hope you physicists went well.
Edit: I'm going home to study chem. These are only the answers I remember, I'm sure Mao or someone will post a completed paper oneday.
Hope this helped!
~pinchies
(Thanks also to onlyfknhuman, BiGDaN, , , , for some I cant remember)
Post by: champorado on November 12, 2008, 01:53:17 pm
What did you get for that lenz's law q?
Post by: thegubble on November 12, 2008, 01:56:20 pm
BBBCBBCCBCDBC
Anyone got the paper home yet?
Post by: onlyfknhuman on November 12, 2008, 02:02:27 pm
ITS P TO Q BECAUSE ITS LEAVING THE FIELD, HENCE IT WANTS MORE FLUX INSIDE THE FIELD HENCE THE FIELD MUST GO IN, USING RIGHT HAND GRIP RULE = P TO Q
i dont remember the questions but i remember the answers see if they click.
EP. 9v
p to q
.036nm i think
97 something
h = 5x10^-15 evs
err....
for that circuit shit p = v^2/R
lm
err... cant remmebe rshit LOl
For sound i got
BBBC
BBCC
CCAC
C
LOL FUCK CANT REMMBER SHIT
Post by: cononthecob on November 12, 2008, 02:03:50 pm
Also, matt freeman = marvin
Post by: champorado on November 12, 2008, 02:06:13 pm
Year 11 seemed harder. Yr 12 physics is like the easiest maths subject in yr 12. Having said that, I still failed. :(
Post by: cononthecob on November 12, 2008, 02:10:36 pm
Post by: onlyfknhuman on November 12, 2008, 02:12:26 pm
Post by: hamtarofreak on November 12, 2008, 02:14:33 pm
I'm pretty sure I got Q->P for the square coil thingo question too - definitely wrote clockwise, can't remember which way around that was though :idiot2:
Post by: matteh on November 12, 2008, 02:15:07 pm
Post by: champorado on November 12, 2008, 02:15:51 pm
note to self: coffee + night time = bad.
Post by: Nelle91 on November 12, 2008, 02:16:00 pm
Post by: onlyfknhuman on November 12, 2008, 02:16:22 pm
Post by: onlyfknhuman on November 12, 2008, 02:17:02 pm
Post by: Robbo on November 12, 2008, 02:17:12 pm
Post by: Nelle91 on November 12, 2008, 02:17:27 pm
Post by: BiG DaN on November 12, 2008, 02:20:42 pm
Power
2. AB
3. 4 x 10^-3
4. 8 X 10^-5
5. B
6.D
7 2.8V
8 C
9 1.6 x 10 ^-6
10 Q to P (think its wrong)
11 48W
12 8V
13 8A (dunno bout this)
14 400 turns
15 0.17
Light
3 4.5
7 5x 10 ^-15 eV
8 2.4
9 0.036
10 3.03
11 arrow from n=4 to 2 with head at 2
12 97nm
SOUND
1. B
2. C (wrong its ment to be B)
3. B
4. C
5. B
6.B
7.B
8.C
9.C
10.C
11.A
12.A
13.D
These r just my answers
Post by: We Want Peace. on November 12, 2008, 02:22:15 pm
wasnt P on the top?>
it said through the square loop.
not the outside path.
Post by: We Want Peace. on November 12, 2008, 02:23:50 pm
I got Q1 BA.
Post by: Nelle91 on November 12, 2008, 02:24:28 pm
Post by: onlyfknhuman on November 12, 2008, 02:25:20 pm
and instead of 8v i got 9v i think
Post by: hamtarofreak on November 12, 2008, 02:25:29 pm
Quote
2. AB
3. 4 x 10^-3
4. 8 X 10^-5
5. B
6. D
7 2.8V
8 C
9 1.6 x 10 ^-6
10 Q to P (think its wrong)
11 48W
12 8V
13 8A (dunno bout this)
14 400 turns
15 0.17
(I hope these are all right, because they're what I got too =P)
Heh, for the second question in Light and Matter I wrote about half a page on how mercury lamps emit light for some reason... :uglystupid2:
Post by: cononthecob on November 12, 2008, 02:27:03 pm
Post by: champorado on November 12, 2008, 02:27:21 pm
Post by: onlyfknhuman on November 12, 2008, 02:27:37 pm
Post by: We Want Peace. on November 12, 2008, 02:28:38 pm
for that gangsta parallel circuit question the answer is 4.8 amps, you had to find the resistance of the whole circuit using 1/R = 1/3 + 1/3 so resistance of parallel lights bit was 1.5, plus wire resistance total of 1 gives R = 2.5, from Ohms V = IR, I = 12/2.5 = 4.8A 8-)
I think u have to seperate the resistance of globe and the wires. ( they are different )
Post by: Macdaddy on November 12, 2008, 02:29:44 pm
Post by: cononthecob on November 12, 2008, 02:32:55 pm
for that gangsta parallel circuit question the answer is 4.8 amps, you had to find the resistance of the whole circuit using 1/R = 1/3 + 1/3 so resistance of parallel lights bit was 1.5, plus wire resistance total of 1 gives R = 2.5, from Ohms V = IR, I = 12/2.5 = 4.8A 8-)
my fuzzix teacher got 4.8 so i assume its right. U gotta add the resistances to find the overall current produced for the whole circuit, which happened to be the current for the point required. what did other people get?
I think u have to seperate the resistance of globe and the wires. ( they are different )
Post by: We Want Peace. on November 12, 2008, 02:33:22 pm
Damn questions 12 and 13, i hate fountains so much now!! the answer was apparantly 9 volts, because you have to include the resistance of the bulb when finding the voltage.
THink 9V is actually the right ans.( Since the smartest guy( nerd? no offence)
in our school got 9V..) so...yeah....doubt my 8 A now
Post by: onlyfknhuman on November 12, 2008, 02:34:40 pm
Post by: fkzbaby on November 12, 2008, 02:35:14 pm
B B B C B B C C C C A A D (sound)
my mate got the same except his 12. was B (hes smartest person ever btw lol)
Post by: onlyfknhuman on November 12, 2008, 02:37:05 pm
I got DBCCCBBCCACCA for the Photonics questions
I'm pretty sure I got Q->P for the square coil thingo question too - definitely wrote clockwise, can't remember which way around that was though :idiot2:for the Vrms question
4 over sqroot 2 same here
Post by: champorado on November 12, 2008, 02:38:40 pm
Did you have to have the rms voltage as an exact value? I think i wrote 2.83 or something.
Post by: Tea.bag on November 12, 2008, 02:39:32 pm
Post by: onlyfknhuman on November 12, 2008, 02:42:57 pm
That fountain question seemed weird. It seemed like something you'd get in Unit 3.
Did you have to have the rms voltage as an exact value? I think i wrote 2.83 or something.
I PUT 2.8v
Post by: onlyfknhuman on November 12, 2008, 02:47:09 pm
I think it was a little harder than last year on a few q's, but mostly easier. Longer too?
Lets begin... 8-)
Magnets & Stuff
--------------------
1. Use rh grip rule, current flowing anti-clockwise
X. Coil leaving Field:
change in flux = final flux - initial flux = zero - into page = out of page. According to lenz law, this change is opposed, hence field set up into page. Via rh grip rule, current flows clockwise, from (p/q I cant remember) to (p/q). Q-P (Clockwise) (unsure-> need mao or someone to confirm. :-\ )
X.Vrms = Vp-p ÷ 2 ÷root(2) (I cant do latex :-( )
8÷2÷root(2) = 2.8V
X Power of spotlight over fountain = 48W
X. Voltage over globe 9v
X. Current in circuit = (0.5Ω*2 + 3Ω÷2 = 2.5Ω therefore 12/2.5 =) 4.8A
X. Power = v^2/R = 40W
X. *V
X. Current at primary = 0.167A
X. 400 turns
Light & Matter & Stuff
------------------------
X. 0.0364nm
X. 97nm
X. h = 5x10^-15 evs
X. 3.03
X. 2.4ev
X. Arrow from n=4 (12.8) to n=2 (10.6) with head at 2
X. Jump from 12.8 -> 0 = max energy = max freq = min wavelength
Photonics & Stuff
--------------------
Syncrotron & Stuff
---------------------
Sound & Stuff
-----------------
1.B
2.B
3.B
4.C
5.B
6.B
7.C (B?)
8.C
9.C (B?)
10.C
11.A (D?)
12.B (C,A?)
13.C (B,D?)
:-) hope you physicists went well.
~pinchies
(Thanks to onlyfknhuman, BiGDaN, , , , for some I cant remember)
got exactly the same except for. that gay q to p shit :( dammit, ur prob right.
and for sound Q 12. definitly the hardest. i put C however :S was juggling between B and C
i assumed that, since their were 3 options for 1. and otpion 2 didnt work. i thought it shouldve worked, =p
Post by: fkzbaby on November 12, 2008, 02:47:27 pm
Total resistance is 3 ohms plus 1 ohm ( bulb + wires )
knowing V=IR
Bulb has 3 x the resistance of the wires therefore 3x the voltage.
so voltage over bulb = 3/4 X 12
= 9V
Post by: Quickclaw on November 12, 2008, 02:48:21 pm
I got DBCCCBBCCACCA for the Photonics questions
I'm pretty sure I got Q->P for the square coil thingo question too - definitely wrote clockwise, can't remember which way around that was though :idiot2:
No simplifying?
Post by: pinchies on November 12, 2008, 02:52:35 pm
Post by: champorado on November 12, 2008, 02:55:05 pm
Post by: Skullmaster4 on November 12, 2008, 02:59:03 pm
I spent like 10 minutes on it and went with P-Q, hope Mao's wrong! :D
Post by: champorado on November 12, 2008, 03:01:27 pm
someone post the exam already! i'm dying here. :'(
Post by: fkzbaby on November 12, 2008, 03:03:55 pm
coz change in flux was upwards, lenzs law gives negative so its back thru the loop (same way as mag field lines)
then RHG rule
Post by: champorado on November 12, 2008, 03:05:04 pm
Post by: lacoste on November 12, 2008, 03:05:17 pm
physics seem incredibly hard with all the maths work? is the math work difficult;are they like formulas ..?
Post by: onlyfknhuman on November 12, 2008, 03:05:27 pm
Post by: pinchies on November 12, 2008, 03:06:23 pm
Mao told me after the exam it was Q-PSorry Skullmaster, if Master Mao said it then it must be true! yay :-D
That one had me waay worried.
Post by: champorado on November 12, 2008, 03:07:16 pm
Post by: pinchies on November 12, 2008, 03:08:02 pm
Edit: Beaten to it. Well, I concur. :-D
Post by: fkzbaby on November 12, 2008, 03:08:23 pm
clockwise i think that was :O
physics is easy
just gotta know what your doing =P
Post by: champorado on November 12, 2008, 03:12:06 pm
Post by: fkzbaby on November 12, 2008, 03:17:58 pm
Post by: dcc on November 12, 2008, 03:19:15 pm
Post by: BiG DaN on November 12, 2008, 03:21:14 pm
2. AB
3. 4 x 10^-3
4. 8 X 10^-5
5. B
6.D
7 2.8V
8 C
9 1.6 x 10 ^-6
10 Q to P (think its wrong)
11 48W
12 8V
13 8A (dunno bout this)
14 400 turns
15 0.17
Light
3 4.5
7 5x 10 ^-15 eV
8 2.4
9 0.036
10 3.03
11 arrow from n=4 to 2 with head at 2
12 97nm
SOUND
1. B
2. C (wrong its ment to be B)
3. B
4. C
5. B
6.B
7.B
8.C
9.C
10.C
11.A
12.A
13.D
can some1 tell me how many i got wrong?
Post by: pinchies on November 12, 2008, 03:21:47 pm
The question specifically asked for whether it was Q to P through the square coil. The current was flowing clockwise, so it went for Q to P.Thanks for that-> it was kind of key to getting it correct! It nearly tripped me up until I read it again. Unfortunately (not for them!) people who may have got lenz law wrong and also missed this may in fact get the question right.
Post by: Nelle91 on November 12, 2008, 03:21:58 pm
Post by: ilovevce on November 12, 2008, 03:22:32 pm
Power
2. AB
3. 4 x 10^-3
4. 8 X 10^-5
5. B (modulus sine graph)
6. D (normal sine graph)
7. 2.83V
8. C
9 1.6 x 10 ^-6
10. Q to P - magnetic flux into page decreases, so opposing magnetic field, produced by the current, goes into the page
to counteract this. Using right-hand rule, current flows anticlockwise. Since it specified direction IN THE SQUARE LOOP, this is from Q to P
11. 48W
12. 9V - V(floodlight) = V(total) x R(floodlight)/R(total) = 12 x (3/4) = 9V
13. 4.8A - I/R(eff) = 1/3 + 1/3 = 1/1.5 >> R(eff) = 1.5ohm >> R(total) = 1.0 + 1.5 = 2.5ohm >> I = V/R = 12/2.5 = 4.8A
14. 400 turns
15. 0.17
Light
1. Incandscent globe > free electrons in conduction band are energized by electrical energy, and they move/vibrate. These vibrations involve many energy transitions, and a continuous spectrum is produced.
2. Incandescent globe - continuous spectrum. Mercury vapour lamp - discrete spectrum
3. Path difference = 4.5cm
4. Minima and maxima spread out, X moves away from W. Using triangle geometry, as base gets smaller, ratio of hypotenuse/other side becomes smaller. Hence distance travelled must be greater for the same path difference.
5. Linear graph of KEmax v. frequency > easiest way is to use eV as units
6. 2.50eV
7. 5.0 x 10^-15 eVs
8. ?
9. 0.036nm
10. ?
11. Arrow from n=4 to n=2 with pointing towards n=2
12. 97nm
SOUND
1. B
2. B
3. B
4. C
5. B
6. B
7. B
8. C
9. C
10. C
11. A
12. B
13. D
Post by: JackOfSpades on November 12, 2008, 03:24:02 pm
Post by: dcc on November 12, 2008, 03:24:43 pm
The question specifically asked for whether it was Q to P through the square coil. The current was flowing clockwise, so it went for Q to P.Thanks for that-> it was kind of key to getting it correct! It nearly tripped me up until I read it again. Unfortunately (not for them!) people who may have got lenz law wrong and also missed this may in fact get the question right.
nps samuel.
Post by: Nelle91 on November 12, 2008, 03:25:18 pm
Post by: mysticus on November 12, 2008, 03:50:01 pm
Post by: grimsy on November 12, 2008, 03:50:33 pm
The question specifically asked for whether it was Q to P through the square coil. The current was flowing clockwise, so it went for Q to P.
i agree with this
Post by: equinox on November 12, 2008, 03:54:28 pm
Post by: ilovevce on November 12, 2008, 03:56:24 pm
Those answers are the same as mine, 'cept for MC 7 in sound, for which I got a C
You're right there. The answer is C. I actually made a typo. Looking at my cheat sheet again I wrote B.
Post by: ilovevce on November 12, 2008, 03:57:42 pm
Those answers are the same as mine, 'cept for MC 7 in sound, for which I got a C
You're right there. The answer is C. I actually made a typo. Looking at my cheat sheet again I wrote B.
Oops. I MEANT I wrote C on the exam. Not B.
Post by: v1ctor on November 12, 2008, 04:09:16 pm
cz that .0364 doesnt ring a bell
Post by: Blizz on November 12, 2008, 04:09:33 pm
Post by: the_head on November 12, 2008, 04:11:04 pm
someone remind me what light qs 9 was again?
cz that .0364 doesnt ring a bell
Something about wavelength in nano meters. Can't give you the exact question.
Post by: sam2703 on November 12, 2008, 04:15:37 pm
it was de broigle stuff
Post by: v1ctor on November 12, 2008, 04:17:00 pm
Post by: sam2703 on November 12, 2008, 04:22:50 pm
Post by: v1ctor on November 12, 2008, 04:25:43 pm
Post by: Mao on November 12, 2008, 04:36:03 pm
need mao
reporting.
anyone want me to actually do the solutions?
Post by: jamestaR` on November 12, 2008, 04:41:00 pm
Sound I got all B and C except one of them was A.
Fuckn piss oisy exam
Post by: pinchies on November 12, 2008, 04:43:13 pm
nps samuel.??? what does nps mean
Post by: iamdan08 on November 12, 2008, 04:50:58 pm
need maoanyone want me to actually do the solutions?
Yes Please! ;D
Post by: chid on November 12, 2008, 05:17:02 pm
Thanks.
Post by: dcc on November 12, 2008, 05:18:05 pm
Yes, we would love it if you could do some solutions. I thinks there were a couple that were tricky. If you can, a scanned solution paper like for spec 2 and methods would be awesome.nps samuel.??? what does nps mean
no problems.