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PHYA1 - Physics Unit 1 Exam - 24th May 2011

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Original post by AlesanaWill
Think I got this too.

I think I may have lost a mark on the one about terminal p.d., didn't explain it very well.

Also, on the question on the back about calculating the energy dissipated per second (or whatever it was), what did everyone get? Was I right to calculate power, P = I^2r, using the internal resistance r?


yep thats what i did :smile:
Original post by AlesanaWill
Think I got this too.

I think I may have lost a mark on the one about terminal p.d., didn't explain it very well.

Also, on the question on the back about calculating the energy dissipated per second (or whatever it was), what did everyone get? Was I right to calculate power, P = I^2r, using the internal resistance r?


To be honest, I've forgotten most of this paper and my answers...save the odd few. :P

Sounds about right for the calculation of energy dissipated per second though.
Reply 242
Original post by Limitless
So calling me a dumbass was just friendly talk?


Oooohhh, is that why you're so butthurt?
In that case sir, I humbly apologise and pray that you may accept my unprecedented vindication. lol.

Another question I wanted to ask: What did you guys put for the question about why we see a vertical line on the oscilloscope trace? I said because the time base is switched off, the dot moves up and down according to the Y-sensitivity (voltage) so fast that we see a line; at the frequency it is going up and down at.
how did everyone get 1.3 A for the second last one. I got 0.67 A because when the current comes at the junction 1/3 goes to where there is more resistance and 2/3 where there is less resistance cause current always goes to where there is less resistance. Also the top bit of the parallel and the bottom bit were in the ratio 2:1.
Reply 244
Original post by Naum
Oooohhh, is that why you're so butthurt?
In that case sir, I humbly apologise and pray that you may accept my unprecedented vindication. lol.

Another question I wanted to ask: What did you guys put for the question about why we see a vertical line on the oscilloscope trace? I said because the time base is switched off, the dot moves up and down according to the Y-sensitivity (voltage) so fast that we see a line; at the frequency it is going up and down at.


I put something similar to you nothing about frequency but did say it was because of an ac voltage. That is why it is going negative and positive.
Reply 245
Original post by Naum
Oooohhh, is that why you're so butthurt?
In that case sir, I humbly apologise and pray that you may accept my unprecedented vindication. lol.

Another question I wanted to ask: What did you guys put for the question about why we see a vertical line on the oscilloscope trace? I said because the time base is switched off, the dot moves up and down according to the Y-sensitivity (voltage) so fast that we see a line; at the frequency it is going up and down at.


I said that too, and said it went in both direction because it was alternating current then :smile:
Original post by Limitless
I put something similar to you nothing about frequency but did say it was because of an ac voltage. That is why it is going negative and positive.


I second this.

Original post by Naum
Proton IS the most stable Baryon.


Protons are notoriously unstable. The answer was Aluminium.
I thought that paper was terrible :frown: think i got between 9 and 15 marks :colondollar:

I thought that there was too many questions on decaying and atoms. I hope grade boundaries are low lol i don't think it will make a difference anyway. :tongue:

Can i sit the exam again in january or will i have to resit all the physics classes again? Was it my imagination or were the questions nothing like other past papers? (the papers i'd done didn't have questions like them)

Also, what was the answer to the question where you had to write the proton number and proton and neutron number (can't remember what it is called) for the one with the alpha decay with 4neutrons and protons and 2 protons?
Original post by lack_of_knowledge
how did everyone get 1.3 A for the second last one. I got 0.67 A because when the current comes at the junction 1/3 goes to where there is more resistance and 2/3 where there is less resistance cause current always goes to where there is less resistance. Also the top bit of the parallel and the bottom bit were in the ratio 2:1.


this would be correct had the question asked for the current value where there was more resistance, but it asked for the current value through the part where there was only one resistor :smile: i imagine you would get a mark for your working as it is all correct, just the answer is incorrect
Original post by buzza786

Original post by buzza786
for the terminal pd as it decrese and curent increase , i reffered to the equations V=W/Q and I=Q/t


You messed this up big time. You were supposed to use the Cosine rule:
a^2-b^2=c^2+Cos(25)
Original post by OpTic Predator
You messed this up big time. You were supposed to use the Cosine rule:
a^2-b^2=c^2+Cos(25)


lolwut.
Original post by MyNeighbourTotoro

Original post by MyNeighbourTotoro
I thought that paper was terrible :frown: think i got between 9 and 15 marks :colondollar:

I thought that there was too many questions on decaying and atoms. I hope grade boundaries are low lol i don't think it will make a difference anyway. :tongue:

Can i sit the exam again in january or will i have to resit all the physics classes again? Was it my imagination or were the questions nothing like other past papers? (the papers i'd done didn't have questions like them)

Also, what was the answer to the question where you had to write the proton number and proton and neutron number (can't remember what it is called) for the one with the alpha decay with 4neutrons and protons and 2 protons?


You cannot retake this exam. If you fail you fail; no two ways about it.

You messed up.
Original post by jackegan93

Original post by jackegan93
What did people put for why the Alpha particle is not affected by the strong nuclear force after it leaves the nucleus?


You had to find the Hypotenuse of the nucleus. You could also have manipulated the rest energy of the proton so it was equal to 1 over the hypotenuse.

When it comes to the strong nuclear force you always use trigonometry.
Original post by OpTic Predator
You had to find the Hypotenuse of the nucleus. You could also have manipulated the rest energy of the proton so it was equal to 1 over the hypotenuse.

When it comes to the strong nuclear force you always use trigonometry.


go back to your quickscoping on mw2 please.
Reply 255
What was the peak to peak voltage of that ac source?
Reply 256
Original post by OpTic Predator
You had to find the Hypotenuse of the nucleus. You could also have manipulated the rest energy of the proton so it was equal to 1 over the hypotenuse.

When it comes to the strong nuclear force you always use trigonometry.


LOL!
Original post by OpTic Predator
You cannot retake this exam. If you fail you fail; no two ways about it.

You messed up.


Oh? how come you're not allowed to resit?
Original post by OpTic Predator
You had to find the Hypotenuse of the nucleus. You could also have manipulated the rest energy of the proton so it was equal to 1 over the hypotenuse.

When it comes to the strong nuclear force you always use trigonometry.


Ok, I like you :P haha
On the page with the question about the feynman diagram i think i didn't see the question about naming the interaction. was there any other questions on that page?

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