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AQA Physics PHYA5 - Thursday 18th June 2015 [Exam Discussion Thread]

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Original post by TheRAG
Yeah found it ok apart from the astro 6 marker, I stated the formula of how to calculate v but didn't do the calculation:angry: and I got a time period of just over 5 days


Ye the 6 marker was difficult, I believe I got the time period to be around 4 days ?


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Original post by SuperMushroom
Can you explain this please?? I calculated the Hubble constant


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The hubble constant is v/d anyway, so doing 1/H you just get d/v, which you might as well calculate from the data straight away.
Original post by SuperMushroom
Can you explain this please?? I calculated the Hubble constant


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I got 4.9 * 10 ^17 , I think thats due to rounding the distance, will I lose marks?
What did the AstroGuys get for the absolute magnitude? Was it -0.097 or a similar number?
Original post by chizz1889
Yes I do, electricity requires a flow of electrons but this was alpha particles not electrons so there wasn't electricity! If it were electrons being deflected by the nuclei I'd agree with you as a magnetic field would be induced but in this case it wont


mate
electricity is flow of charge
Original post by TheRAG
What did the AstroGuys get for the absolute magnitude? Was it -0.097 or a similar number?


- 9.7 * 10 ^ -3
Original post by TheRAG
What did the AstroGuys get for the absolute magnitude? Was it -0.097 or a similar number?


I got -8.7 * 10^-3
So about an order of magnitude smaller.
Original post by TheRAG
What did the AstroGuys get for the absolute magnitude? Was it -0.097 or a similar number?


I got that number exactly


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PHYA5D; Turning points was relatively standard, majority of the the section A everyone sat was good, the QWC was good, the paper as a whole was nice. I'm unsure on boundaries as there was one year the cap was 67 for 5D, aside from that it lies around 58-60, and this years was harder than last because last years was very easy but had great UMS. I'd probably say it's around 63 cap from previous papers. Thoughts?


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Original post by DomRauba
- 9.7 * 10 ^ -3


Wasn't it -8.7*10^-3
Original post by chizz1889
Yes I do, electricity requires a flow of electrons but this was alpha particles not electrons so there wasn't electricity! If it were electrons being deflected by the nuclei I'd agree with you as a magnetic field would be induced but in this case it wont


You're missing the point entirely. The electromagnetic force is in play, that has nothing to do with whether "electricity" was present.

Electromagnetism is a field of physics, and may refer only to changing electric fields and induced magnetism.

But the electromagnetic force is one of the four fundamental forces of nature, and is in play in this question.
Original post by StarvingAutist
I got -8.7 * 10^-3
So about an order of magnitude smaller.


oops i meant -0.0097
Original post by TheRAG
What did the AstroGuys get for the absolute magnitude? Was it -0.097 or a similar number?


Depends on exactly what value you read from the graph, but a correct answer should have been very close to 0, either positive or negative.
Original post by k9000
I know so am i


nevertheless, it won't be that high, maybe 63 for full ums
For the assumption ii said in (bold letters : MOVING ) particles would that exclude some of the assumption for those answers? I put perfectly elastic between collisions and move randomly and rapidly?
Original post by StarvingAutist
About 4.8*10^17 s so around 15 billion years. I just did d/v because there was no point calculating the hubble constant. Are you allowed to do that?

Precisely what I did
what did everyone get for the radius in the astro, can't remember what it was the radius of tho
Original post by MangoFreak
You're missing the point entirely. The electromagnetic force is in play, that has nothing to do with whether "electricity" was present.

Electromagnetism is a field of physics, and may refer only to changing electric fields and induced magnetism.

But the electromagnetic force is one of the four fundamental forces of nature, and is in play in this question.


We can argue this all day haha but yeah I agree with your last paragraph. However electrostatic force is a type of electromagnetic force but all electromagnetic forces aren't electrostatic forces as it's not always a static field. Do u get what I'm trying to say now?
Original post by RemainSilent
For the assumption ii said in (bold letters : MOVING ) particles would that exclude some of the assumption for those answers? I put perfectly elastic between collisions and move randomly and rapidly?

Varying KE and random motion no preferred direction of motion
Unofficial mark scheme?

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