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

Original post by CD223

Oh right! That sounds really odd!

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Might have been on one of the 2011 papers, you should come across it anyway!

Reply 402

Original post by Lau14

Might have been on one of the 2011 papers, you should come across it anyway!

I think I'll attempt that tomorrow. Thank you!

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Reply 403

TheRAG

Original post by Lau14

Not that I can think of? There was one six marker on finding acceleration or something involving capacitors which threw me for a moment but made sense after doing part b anyway!

I've done this one and it reminds me of an ISA style question. Take measurements for initial and final pd and use the exponential formula for V. Then use suvat for the acceleration.

Reply 404

Original post by TheRAG

I've done this one and it reminds me of an ISA style question. Take measurements for initial and final pd and use the exponential formula for V. Then use suvat for the acceleration.

Yeah it did turn out like that very easily, and if you moved onto the second part of the question first you had to actually do some calculations so that helped you figure out what you needed to measure for the six marker! :smile:

Reply 405

Can somebody help me please?

I've done the JUN12 PHYA5 paper and I've come across questions that I am pretty baffled on.

It is Q3(b)(i) and (ii)

I don't understand why they use the area of a sphere in the calculation and why they take the value of r as 0.18 for (i).

JUNE 12 QP

JUNE 12 MS

Thanks in advance :smile:

(edited 9 years ago)

Reply 406

Original post by Disney0702

As the source emits gamma uniformly in all directions, it's effectively an expanding sphere of radiation. So 0.18m away (where the detector is), overall the gamma rays will have spread equally out over an area equal to the surface area of a sphere with radius 0.18m (as the centre of the sphere will be the source), and the ratio will be area of detector/area of sphere because area will be directly proportional to number of gamma photons.

Reply 407

Original post by Lau14

Ah thank you so much, I understand it so much better now :smile:

I'm sorry to ask again but I am still quite stuck on Q3(b)(ii) and as for Q3(c) I just wanted to know if count rate is the same as intensity.

Reply 408

Original post by Disney0702

Ah thank you so much, I understand it so much better now :smile:

I'm sorry to ask again but I am still quite stuck on Q3(b)(ii) and as for Q3(c) I just wanted to know if count rate is the same as intensity.

For 3bii. the count rate given will be 1/400th of the actual rate recieved by the detector, so you'll need to multiply by 400 to account for that, and divide by the ratio from part i to find out the activity for the whole sphere (so from the source) rather than just the activity detected.

3c. I'm really not sure to be honest sorry!

Reply 409

Original post by Lau14

Thank you very much :smile:

Reply 410

frankiejayx

do we need to know all the experiments for testing the gas laws? :confused:

]

Reply 411

Original post by frankiejayx

do we need to know all the experiments for testing the gas laws? :confused:

]

I assume that we should it could come up as a 6 marker

Reply 412

frankiejayx

Original post by Disney0702

I assume that we should it could come up as a 6 marker

Okay thanks!

Reply 413

Original post by TheRAG

I've done this one and it reminds me of an ISA style question. Take measurements for initial and final pd and use the exponential formula for V. Then use suvat for the acceleration.

Original post by Lau14

Gonna attempt this paper tomorrow. See if I can understand it! (Probably won't despite the hints...)

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Reply 414

Original post by CD223

Gonna attempt this paper tomorrow. See if I can understand it! (Probably won't despite the hints...)

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Good luck! :smile:

Reply 415

Original post by Lau14

Good luck! :smile:

Thank you! College Monday 😥😥

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Reply 416

Original post by CD223

Thank you! College Monday

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I've already been back a whole week :/ it doesn't feel like anything's really gotten done either, just another week closer to exams!

Reply 417