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

Original post by _Caz_

Yes it is

What topic is that ratio relevant to?

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Reply 501

Original post by CD223

What topic is that ratio relevant to?

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Evidence for the big bang theory. There are 3 hydrogens to every one helium in the universe. It's to do with the heat at the start of the universe - it was hot enough for protons/neutrons to fuse into hydrogen.

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Reply 502

Original post by _Caz_

Ah, it makes sense that I don't know that yet then... Covering the Big Bang theory in my next lesson! Thanks for the info though :smile:

Reply 503

Original post by CD223

Ah, it makes sense that I don't know that yet then... Covering the Big Bang theory in my next lesson! Thanks for the info though :smile:

No problem! :smile:

Reply 504

Original post by _Caz_

No problem! :smile:

Is there any hard topics beyond the Doppler effect?

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Reply 505

TheRAG

Original post by CD223

Is there any hard topics beyond the Doppler effect?

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Lens calculations and resolving power for me

Reply 506

Original post by CD223

Is there any hard topics beyond the Doppler effect?

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I find the concept of parallax the most difficult thing in the whole topic. There's nothing harder than that in the whole unit. The only thing that is a little bit tricky is the units when using Hubble's constant but other than that I think you'll be okay :smile:

Reply 507

Original post by TheRAG

Lens calculations and resolving power for me

By lens calculations do you mean using that specific equation (1/f=...), or just the whole topic to do with magnification, power, collecting areas etc?

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Reply 508

Original post by _Caz_

Oh right I think Hubble's constant is Tuesday's lesson!

Could you kindly explain how to convert between parsecs and metres? Do I just have to "remember" 1pc = 3.08x10^16 m?

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Reply 509

JaySP

Has anyone done the exam questions by topic on physicsandmathstutor.com? I'm finding it really hard. I think a lot of the questions are legacy spec, so may be more difficult. Anyone had any experience?

Reply 510

Original post by JaySP

I'm personally sticking to the current set of papers. I know they're limited but it's a better indication of what the exam wil be like.

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Reply 511

JaySP

Original post by CD223

I'm personally sticking to the current set of papers. I know they're limited but it's a better indication of what the exam wil be like.

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I may join you there as I'm frankly finding this a little disheartening. What are you using to practice?

Reply 512

Original post by JaySP

I may join you there as I'm frankly finding this a little disheartening. What are you using to practice?

I'm using the CGP guide, my own notes, the Nelson Thornes book and gonna start on past papers ASAP this week.

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Reply 513

Lau14

Original post by CD223

Oh right I think Hubble's constant is Tuesday's lesson!

Could you kindly explain how to convert between parsecs and metres? Do I just have to "remember" 1pc = 3.08x10^16 m?

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It's on the data sheet, all the conversions for parsecs to lightyears/metres etc, under the astro heading :smile:

Reply 514

Original post by Lau14

It's on the data sheet, all the conversions for parsecs to lightyears/metres etc, under the astro heading :smile:

Much appreciated! I should look at that before the exam...

What are you doing in class at the minute? We have 3 lessons left before we finish astro, then the EMPA on the 5th :smile:

Reply 515

Lau14

Original post by CD223

Much appreciated! I should look at that before the exam...

What are you doing in class at the minute? We have 3 lessons left before we finish astro, then the EMPA on the 5th :smile:

EMPA prep/mocks recently, EMPA practical this coming week, then revision or something I expect :smile:

Reply 516

Original post by Lau14

EMPA prep/mocks recently, EMPA practical this coming week, then revision or something I expect :smile:

Sounds good! I got 3 EMPA section B papers done today which was okay - hard to do the questions that rely on part A data of course, but I guess some questions regarding proving relationships and reducing uncertainty etc could be useful.

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Reply 517

Lau14

Original post by CD223

Yeah I plan to mostly read through the ones that rely on the practical bit and see if I have any idea what it's on about to be honest :tongue:

might to the other question properly though. How did you find them?

Reply 518

Original post by Lau14

Yeah I plan to mostly read through the ones that rely on the practical bit and see if I have any idea what it's on about to be honest :tongue:

might to the other question properly though. How did you find them?

That makes sense! They were really hard if I'm honest. Not sure if that's because I didn't do the part As for them or what. It just was difficult to comprehend what the questions asked.

I'm desperate for at least a C this year lol.

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Reply 519