ATAR Notes: Forum

Archived Discussion => 2009 => End-of-year exams => Exam Discussion => Victoria => Physics => Topic started by: Flaming_Arrow on November 11, 2009, 07:54:11 pm

Title: PHYSICS EXAM 2 SUGGESTED SOLUTIONS
Post by: Flaming_Arrow on November 11, 2009, 07:54:11 pm: Electric power:
1. alternator
2. 8.0X10^(-3)T
3. 3.6X10^(-4)V
4. diagram
5. up
6. 0.0045N
7. 0 N
8.
9.1.00X10^4W
10. 4000W
11. 300V
12. 5000VRMS
13. 480 turns
14. 40.0W
15 498VRMS
16. T=0.040s, Vpeak=50V

Light and matter:
1. interference - wave property
2.
3. Thelma, same distance, constructive, bright
4. 496nm
5.
6. h=5.0X10^(-15)eVs, Work function=1.5V (no minus)
7. i) max k. e. not affected, ii) double
8. 8.9X10^3eV
9. 4.7X10^(-24)kgms-1
10.
11. first to second, first to third
12.Whole number of standing waves around nucleus.

Synchrotron
CBCBCDDBCBACB

Photonics
CCADBCBBBCBCA

Sound
BBCBCDCCBCAAA

got it from itute
Title: Re: PHYSICS EXAM 2 SUGGESTED SOLUTIONS
Post by: ngRISING on November 11, 2009, 07:56:11 pm: LOOOOOOOOOL. I GOT 2 MC WRONG. HAHA. AWESOME (Y). your the best flaming arrows + itute.
Title: Re: PHYSICS EXAM 2 SUGGESTED SOLUTIONS
Post by: THem on November 11, 2009, 07:57:12 pm: What's question 8? - Electric power

Whats question 2,5 and 10 of light?
edit: 2 - photoelectric effect?
5 - describing ekmax, w and f?
10 - bright band explanation?
Title: Re: PHYSICS EXAM 2 SUGGESTED SOLUTIONS
Post by: poppa on November 11, 2009, 09:35:30 pm: for sound question 4, anyone 100 % sure the answer is B, not C?
Title: Re: PHYSICS EXAM 2 SUGGESTED SOLUTIONS
Post by: appianway on November 11, 2009, 09:38:40 pm: The sound answer for question 4 is definitely B. Think about what the waveform behind the displacement of 0 (presuming it's a distance from the speaker when the displacement starts being measured anyway). Most people I know put down B, and my teacher said that the answer's B.
Title: Re: PHYSICS EXAM 2 SUGGESTED SOLUTIONS
Post by: poppa on November 11, 2009, 09:42:18 pm: Quote from: appianway on November 11, 2009, 09:38:40 pm
The sound answer for question 4 is definitely B. Think about what the waveform behind the displacement of 0 (presuming it's a distance from the speaker when the displacement starts being measured anyway). Most people I know put down B, and my teacher said that the answer's B.
thanks for the fast ans
i lost 2 marks there :(
Title: Re: PHYSICS EXAM 2 SUGGESTED SOLUTIONS
Post by: KeyMan on November 11, 2009, 10:03:15 pm: Can someone explain why question 15 is 498RMS?

I got 480V for question 15.

P = VI
10000 = 5000I
I = 2.0A

V_drop = IR
= 2.0 * 10
= 20V

500 - 20 = 480V
Title: Re: PHYSICS EXAM 2 SUGGESTED SOLUTIONS
Post by: crappy on November 11, 2009, 10:04:56 pm: Quote from: KeyMan on November 11, 2009, 10:03:15 pm
Can someone explain why question 15 is 498RMS?

I got 480V for question 15.

P = VI
10000 = 5000I
I = 2.0A

V_drop = IR
= 2.0 * 10
= 20V

500 - 20 = 480V

You got 480V without the transformers Im guessing. The second part had transformers in it, so there is a massive difference in working D:
Title: Re: PHYSICS EXAM 2 SUGGESTED SOLUTIONS
Post by: /0 on November 11, 2009, 10:05:33 pm: You apply $V_{drop} = 20V$ to the stepped-up voltage, since the voltage loss occurs where the voltage has been stepped up.
So the voltage delivered to the second transformer is $5000-20 = 4980V$

Then you step this down by 10x to get 498V
Title: Re: PHYSICS EXAM 2 SUGGESTED SOLUTIONS
Post by: KeyMan on November 11, 2009, 10:07:11 pm: Ah damn it! Subtracted 20 from the wrong voltage :(

Thanks for explanation.

I should get 2 out of the 3 marks though yeh? :P
Title: Re: PHYSICS EXAM 2 SUGGESTED SOLUTIONS
Post by: nem0 on November 11, 2009, 10:36:55 pm: i dont see itute answers? are they even up?
Title: Re: PHYSICS EXAM 2 SUGGESTED SOLUTIONS
Post by: majo on November 12, 2009, 02:45:25 am: i think i only lost 5 marks. I did the loop for the solenoid the wrong way, feel like such a doosh bag :(

what do you guys think will be the a+ cutoff?

i think i lost between 5 and 8. depending on how good my explanation for question 2 of light and matter!