Physics Aftermath

adam_ccfc

I don't see why people did Q3 and are now moaning about it!

I'm not defending the way it was asked, but as soon as I saw what was entailed, I just decided to do the other 3 experiments!

Dermot2468

Dont know if ye know already but the papers up now
http://www.examinations.ie/archive/exampapers/2007/LC021ALP000EV.pdf

JC 2K3

adam_ccfc wrote:

I don't see why people did Q3 and are now moaning about it!

I'm not defending the way it was asked, but as soon as I saw what was entailed, I just decided to do the other 3 experiments!

But if you didn't know how to heat the copper due to the dept telling you you didn't have to know how, you had no choice...

Q3 wasn't so bad anyway. There was 18 marks for the second section. My guess is 12 for the graph and 6 for working out f, and if you got f without working it out from the graph I'd say they'd give you 3.

adam_ccfc

JC 2K3 wrote:

I wrote that it affects a photographic plate, right?

See my post above.

Gangsta

ZorbaTehZ wrote:

Net force is zero at 0.085m (point of equilibrium)

EDIT: nub

I got all dem answers but when it's stretched is the amplitude not 310mm-285mm and the pt of equilibrium is 285mm?

adam_ccfc

JC 2K3 wrote:

But if you didn't know how to heat the copper due to the dept telling you you didn't have to know how, you had no choice...

Q3 wasn't so bad anyway. There was 18 marks for the second section. My guess is 12 for the graph and 6 for working out f, and if you got f without working it out from the graph I'd say they'd give you 3.

Fair enough, I was looking for full marks though so I didn't chance it.

carlowboy

Where the feck is the IR light and photographic plate coming from????

adam_ccfc

carlowboy wrote:

Where the feck is the IR light and photographic plate coming from????

I have the 'Real World Physics' book by Dan O'Regan, and it lists the effect on photographic plates and the heating effect (by using a blackened thermometer bulb) as methods of detecting IR light. They're what I put down.

ZorbaTehZ

@Gangsta: Amplitude is the distance between the maximum displacement and the point of equilibrium, so by that logic it must be at 285mm - why do you think it could be 280mm? (so I can follow your train of thought)

carlowboy

Ohhh....I get you now.... just as well I had 8 out of the other 9 eh?

adam_ccfc

carlowboy wrote:

Where??????Question 2?

Yep, asked how IR light was detected.

ron-burgandy

Do you think I'll get marks for infrared goggles?!

carlowboy

sarcastic fecker!
If you knew the other ones, you needn't have bothered.

madgal

I did a mini graph on my exam paper and they both looked the same.

RandolphEsq

madgal wrote:

http://img485.imageshack.us/img485/567/physicsts7.jpg

That was my graph lol!! It didnt look right, but at that stage I was in despair and couldn't give a damn.

Does the 1/V not go on the Y-Axis for that experiment?

adam_ccfc

BrightEyes wrote:

Does the 1/V not go on the Y-Axis for that experiment?

Yeah, sure does.

carlowboy

BrightEyes wrote:

Does the 1/V not go on the Y-Axis for that experiment?

Does it make a difference? The long answer is....no.

carlowboy

ron-burgandy wrote:

Do you think I'll get marks for infrared goggles?!

I don't think that can detect infrared light though can it? It gives off infrared light.

microbiek

Ir goggles and thermal imaging and a themometer

carlowboy

I dunno... I didn't do that part.

Feddd

I was going for an A1 but don't think I got it and it doesn't matter that people say they will mark the hard questions easier because its the questions everyone thought were fine I didn't get out! Just made loads of silly mistakes really. =/

Q6 for some reason I got the extention wrong in both part (ii) and (iii). just wasn't thinking. In part (ii) I got all the other numbers right so I'll prolly get most of the marks? And in part (iii) I had the logic right and gave a little explanation at the start but said wrong number: Because acceleration is proportional to displacement from the fixed point, when the acceleration is 0 the displacement from the point is 0. Hence, the length of the spring when accelleration is 0 is 200mm or .2m. >.< :mad: :mad: :mad:
So hopfully I'll only get docked a few marks in Q6.

scorzny

what did u guys get for the junction voltage of the diode from experiment 4??:eek:

microbiek

scorzny wrote:

what did u guys get for the junction voltage of the diode from experiment 4??:eek:

0.6v what you get?

carlowboy

Scorzny, isn't that where it hits the x-axis? I can't quite remember off hand.

I got .57v thinking back, because that's where it hits the axis for mine.

microbiek

Feddd wrote:

I was going for an A1 but don't think I got it and it doesn't matter that people say they will mark the hard questions easier because its the questions everyone thought were fine I didn't get out! Just made loads of silly mistakes really. =/

Q6 for some reason I got the extention wrong in both part (ii) and (iii). just wasn't thinking. In part (ii) I got all the other numbers right so I'll prolly get most of the marks? And in part (iii) I had the logic right and gave a little explanation at the start but said wrong number: Because acceleration is proportional to displacement from the fixed point, when the acceleration is 0 the displacement from the point is 0. Hence, the length of the spring when accelleration is 0 is 200mm or .2m. >.< :mad: :mad: :mad:
So hopfully I'll only get docked a few marks in Q6.

no because the weights still on it so its 285mm

scorzny

cool,i showed a range between say .6 and .75,i put down .7 as my answer,they'll probably allow for that!?

microbiek

carlowboy wrote:

Scorzny, isn't that where it hits the x-axis? I can't quite remember off hand.

I got .57v thinking back, because that's where it hits the axis for mine.

yeah its like that on mine but i just said 0.6 because thats what it is for silicon

Feddd

scorzny wrote:

what did u guys get for the junction voltage of the diode from experiment 4??:eek:

Junction voltage. Does that basically mean when the current starts getting far bigger per volt? It says estimate from your graph so I think anywhere between .6 and .7 is ok?

scorzny

carlowboy wrote:

Scorzny, isn't that where it hits the x-axis? I can't quite remember off hand.

I got .57v thinking back, because that's where it hits the axis for mine.

Its where it hits the curve where the curve begins to get steep all of a sudden i think!~

microbiek

scorzny wrote:

cool,i showed a range between say .6 and .75,i put down .7 as my answer,they'll probably allow for that!?

can it b ova 0.6


yeah where it starts gettin steep