# OCR B (Advancing Physics) - Section CWatch

This discussion is closed.
13 years ago
#61
I'm just being dumb now... I even did a 15 page coursework on SUVAT...

I think I need sleep... good night all, thanks for the help dinky and math - good luck with the exam(s) tomorrow.
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13 years ago
#62
question:

For the double slit experiment, the 1st maxima occurs when there is a whole number of wavelength (for path difference)

i.e. n*lambda = dsin(theta)

for single slit (showing the intensities), a whole number of wavelength corresponds to a MINIMA
but for the double slit, it will still show a variation of intensities...when will the 1st minima occur for this? will it be for half number of wavelengths or whole number?
#63
(Original post by Mathemagician)
question:

For the double slit experiment, the 1st maxima occurs when there is a whole number of wavelength (for path difference)

i.e. n*lambda = dsin(theta)

for single slit (showing the intensities), a whole number of wavelength corresponds to a MINIMA
but for the double slit, it will still show a variation of intensities...when will the 1st minima occur for this? will it be for half number of wavelengths or whole number?
For single slit, bsintheta = nlambda where b is the slit WIDTH, no? That's where there's a minimum. Minimum for double slit is a odd half number of wavelengths... i think...
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13 years ago
#64
(Original post by dinkymints)
For single slit, bsintheta = nlambda where b is the slit WIDTH, no? That's where there's a minimum. Minimum for double slit is a odd half number of wavelengths... i think...
yeah thats true, but there still is a vary in intensity for the double slit (sharper at the central maxima, less intense at the edges).
#65
(Original post by Mathemagician)
yeah thats true, but there still is a vary in intensity for the double slit (sharper at the central maxima, less intense at the edges).
Yeah, I'm not really sure why that is... can't be the same reason as for single slit can it... it's the fringes themselves that get less intense towards the outsides, not fringe by fringe... so can't be to do with the wide angles etc...
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13 years ago
#66
(Original post by dinkymints)
Yeah, I'm not really sure why that is... can't be the same reason as for single slit can it... it's the fringes themselves that get less intense towards the outsides, not fringe by fringe... so can't be to do with the wide angles etc...
The maxima will vary as a whole number of wavelengths. So the maxima intensities must also vary as a whole number of a wavelength (and mimima as half wavelengths) when it is for double slit.

sorry for the confusion
#67
(Original post by Mathemagician)
The maxima will vary as a whole number of wavelengths. So the maxima intensities must also vary as a whole number of a wavelength (and mimima as half wavelengths) when it is for double slit.

sorry for the confusion
lol, im more confused than ever... time for bed i think!

Good luck!
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13 years ago
#68
(Original post by dinkymints)
lol, im more confused than ever... time for bed i think!

Good luck!
ohh sorry!

good luck

*Im not taking the paper tomorrow*
13 years ago
#69
Hi!

What did everyone think of the exams 2 day? They werent 2 bad, got most marks on secion C's i think!
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13 years ago
#70
I don't understand how they get away with producing the same paper every year.

The section C questions were basically identical to previously (bar the refractive index one which wasn't really Sect. C Style).

Section A and B were ok too in both papers I thought.
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13 years ago
#71
I found it ok. Except that question about the lorry. I think i got marks on it but only because i was messing about with the numbers to find an answer which sounded right. What was the answer to question 9 final part?
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13 years ago
#72
I got some ridiculous number for the stopping distance... I had no idea how to do that bit but the rest was pleasantly easy actually... prove this and prove that all you have to do is divide or multiply and see what's right and write it down lol... as for Section C I ran out of stuff to say in both papers (but more so in the second one). I answered the short answer, specific ones but that last part on Understanding Processes worth 6 marks was a bit gay really... I waffled a lot, I hope I get some marks...
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13 years ago
#73
(Original post by TheCI)
I found it ok. Except that question about the lorry. I think i got marks on it but only because i was messing about with the numbers to find an answer which sounded right. What was the answer to question 9 final part?
I think i got something like 38m. Cos you had to use the kinetic energy you'd worked out, find the gravitional potential energy and equate them so that it equalled the Work Done.
so KE + GPE = WD
then WD = Force x Distance
so i used the frictional force (32kN i think it was) and then found the distance from the above equation
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13 years ago
#74
Hmm.. I didn't have a clue what to do for that last part on the lorry.
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13 years ago
#75
rmyl's right, i got that too, same method
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13 years ago
#76
wahey, u got the same thing for the lorry! thank u very much for that.did any one actually finish with enough time to check?
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#77
(Original post by HollyJa)
wahey, u got the same thing for the lorry! thank u very much for that.did any one actually finish with enough time to check?
Yes, but I couldn't come up with comfortable answers for things like defining polycrystalline and noise
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13 years ago
#78
I think noise is random fluctuation of a signal due to interference.
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13 years ago
#79
(Original post by dinkymints)
Yes, but I couldn't come up with comfortable answers for things like defining polycrystalline and noise
i think i got the noise one, can't remember. But not about polycrystalline, couldn't remember that for my life. I just went on about areas of crystalline structure arranged randomly together or something. It didn't sound like i knew what i was talking about at all!!!
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13 years ago
#80
i was quite pleased with the two papers, more-so for the UP paper that was rather easy indeed. except the lorry question which i didnt have a clue about so i messed it up probably, and also the refractive index question wasnt somthing i expected in section c. i was very pleased that they didnt ask anything about quantum behaviour in section C. what did people do for thier section C's. for the wave superposition i did the two speakers and interference causeing loud and quiet spots. for another one i did the distance from a ship to an iceburg, and i cant remember what i did for the other one.
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