# Jun:28.... PHY6.. how was it??Watch

This discussion is closed.
14 years ago
#61
(Original post by Hoofbeat)
But in the question it told you they both produced energies of something like 20MeV so that won't be a marking point.

I got a sine wave for the dynamo - anyone else?
Oddly enough i also put a sine wave for the dynamo, i figured the induced 'I' should rise and fall, and would change from +ve to -ve, +ve to -ve, cuz of the magnet changing direc relative to the field ie going towards it and then away (to cut da flux), or something like that.
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14 years ago
#62
Oddly enough i also put a sine wave for the dynamo, i figured the induced 'I' should rise and fall, and would change from +ve to -ve, +ve to -ve, cuz of the magnet changing direc relative to the field ie going towards it and then away (to cut da flux), or something like that.
That's basically what I thought too. Glad someone else agrees with me - a straight line graph seemed too damn obvious!
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14 years ago
#63
Yep.
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14 years ago
#64
Oddly enough i also put a sine wave for the dynamo, i figured the induced 'I' should rise and fall, and would change from +ve to -ve, +ve to -ve, cuz of the magnet changing direc relative to the field ie going towards it and then away (to cut da flux), or something like that.
i did a cos wave... but im sure it depends on if the magnet was already rotating before and which position it is in at the instance the graph starts... i think cos wave might still get me the marks for that
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14 years ago
#65
I put a straight line... as i thought that as the bike was at a constant speed the current would be constant
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14 years ago
#66
(Original post by Hoofbeat)
But in the question it told you they both produced energies of something like 20MeV so that won't be a marking point.

I got a sine wave for the dynamo - anyone else?
It doesn't mean that VdG *couldn't* be used to produce higher-energy/different energy particles. I think it actually said only the radioactive source had particles with energy 2MeV.. but am not sure.
14 years ago
#67
(Original post by Hoofbeat)
But in the question it told you they both produced energies of something like 20MeV so that won't be a marking point.

I got a sine wave for the dynamo - anyone else?
Isn't the output on a dynamo always DC because of the commutator though?
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14 years ago
#68
bugger, I just looked it up and yes the dynamo output graph is definitely "wiggly"

Another question down the drain.
14 years ago
#69
yeh it is a sin graph, just looked it up...damn i put a straight line with a negative gradient..
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14 years ago
#70
i thought the paper was kinda simple although not as simple as jan 2004

the only mistake i made for the entire paper was the calculation at where you were supposed to find the k value...to those taking medical physics...its like finding the coefficient of reflection but without the square root...
i rooted it...cause i was thinking that it was the reflection coeeficient from medical physics...read the thing wrongly...and therefore my graph went wild !!..

but oh well..the rest was just nice....btw...why does the picture has a shadow on the right side??anyone knows???i explained in terms of frequency
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14 years ago
#71
(Original post by MalaysianDude)
anyways about the graph thing...id have to say that the graph would hav ea straight line but at the negative gradient...how do i know that??i refered to the formula and noticed a negative sign there and basically put it as the negative gradient...and that im 100% sure thats the answer...
Unfortunately, you are 100% wrong there if you are referring to dynamo output. Look it up in a textbook - it's a wave.

rosie.
14 years ago
#72
I thought it was a good paper, one of the best suited to me, could have been much worse.
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14 years ago
#73
(Original post by crana)
bugger, I just looked it up and yes the dynamo output graph is definitely "wiggly"

Another question down the drain.
I got my dynamo graph as a sine curve but slightly skewed, the gradient raises slowly but drops down towards the ordinate quite steeply? Is that what the pic shows in the textbook?
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14 years ago
#74
(Original post by Mysticmin)
I got my dynamo graph as a sine curve but slightly skewed, the gradient raises slowly but drops down towards the ordinate quite steeply? Is that what the pic shows in the textbook?

well lol it was in my gcse physics revision guide so its not particularly detailed, but in the piccy it looks like each up & down bit (n or u shapes) are symmetrical
14 years ago
#75
(Original post by Mysticmin)
I thought it was a good paper, one of the best suited to me, could have been much worse.
hey mysticmin... i thought the same...
funny that the question you asked me yesterday came up
i think the cyclotron bit is just stuck there so it wont look suspicious
lol

(im joking... its quite a common topic... before mysticmin's house gets raided )
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14 years ago
#76
(Original post by crana)
well lol it was in my gcse physics revision guide so its not particularly detailed, but in the piccy it looks like each up & down bit (n or u shapes) are symmetrical
Damn, I thought the current induced would be stronger the nearer the pole of the magnet was to the solenoid because of a stronger magnetic flux. Urgh, another wrong fact.

Thanks S1M Perhaps I'm just psychic? Nah, I was hectically revising during my 2 hr break between economics and physics, psychic I am not...
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14 years ago
#77
(Original post by Mysticmin)
Damn, I thought the current induced would be stronger the nearer the pole of the magnet was to the solenoid because of a stronger magnetic flux. Urgh, another wrong fact.
you could be right i spose? I mean it is only GCSE after all that the book showed.
14 years ago
#78
(Original post by crana)
you could be right i spose? I mean it is only GCSE after all that the book showed.
I don't have that much faith in graphs I deduce
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14 years ago
#79
(Original post by Mysticmin)
Thanks S1M Perhaps I'm just psychic? Nah, I was hectically revising during my 2 hr break between economics and physics, psychic I am not...
lol... im just kidding with ya... thanks... i would not have gone over it in as much detail if it wasn't for you you got me some marks
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14 years ago
#80
(Original post by S1M)
lol... im just kidding with ya... thanks... i would not have gone over it in as much detail if it wasn't for you you got me some marks
Yay! That paper was lucky, it didn't ask me anything to do with the rather large holes in my synoptic knowledge
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