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

You are a godsend! Thanks so so much

No problem!
Just to let you know know there is a typing error in the last bit of the second point. I meant to say protons and neutrons (constituents of all nuclei) have a greater mass when they are separated.
I said they have a greater mass when they joined which is incorrect!
Edit: ignore me, i used the word "than" which makes it fine :smile:

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(edited 8 years ago)

Reply 1581

Sbarron

3

Original post by cajach

I get it too now! Glad we could help each other out :h:

Good luck in the exam!

And good luck to you too!!

Reply 1582

Absent Agent

21

Original post by Sbarron

Yaaaayy I finally get it!!! It's all about wether the reaction needs energy supplied to make it happen or wether it happens naturally due to instability!
So in fission (breaking a nuclei into all it's constituent parts) energy would be required so a greater mass in the products.
In natural fission (including the bombardment of uranium) you are releasing energy to make more stable products so the mass of the products is less!!!

😊

You've understood it better than me :smile:

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Reply 1583

Sbarron

3

Original post by Mehrdad jafari

No problem!
Just to let you know know there is a typing error in the last bit of the second point. I meant to say protons and neutrons (constituents of all nuclei) have a greater mass when they are separated.
I said they have a greater mass when they joined which is incorrect!
Edit: ignore me, i used the word "than" which makes it fine :smile:

Posted from TSR Mobile

The one last thing that doesn't make sense it that for helium fusion we release energy so get lower mass but we need energy to overcome the electrostatic force (hence high temps)

So I'm guessing the energy required is negligible in comparison to energy released right?

Reply 1584

AR_95

21

Original post by Sbarron

The one last thing that doesn't make sense it that for helium fusion we release energy so get lower mass but we need energy to overcome the electrostatic force (hence high temps)

So I'm guessing the energy required is negligible in comparison to energy released right?

Yes because you're using the energy to overcome the repulsion so it isn't available to become mass

Reply 1585

Sbarron

3

Original post by Mehrdad jafari

You've understood it better than me :smile:

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Haha I doubt that... Anyway thanks for helping I think a fresh mind this morning was required!
After all this I bloody well hope it comes up!!

Reply 1586

Sbarron

3

Original post by AR_95

Yes because you're using the energy to overcome the repulsion so it isn't available to become mass

Oh yes of course!

Reply 1587

AR_95

21

Original post by Sbarron

Oh yes of course!

You're right though, the word Release is a headache in this topic

Reply 1588

Sbarron

3

After spending hours upon hours trying to understand fusion and fission it better bloody come up in the exam this week otherwise I'm going to literally explode and release enough energy to create the next Big Bang!!!

Reply 1589

Sbarron

3

Original post by AR_95

You're right though, the word Release is a headache in this topic

Also I like to think of 'unbinding' rather than 'binding' sometimes

Reply 1590

gcsestuff

2

Original post by Sbarron

After spending hours upon hours trying to understand fusion and fission it better bloody come up in the exam this week otherwise I'm going to literally explode and release enough energy to create the next Big Bang!!!

I'm praying for a lovely 15 marks on fission and the nuclear reactor too. Maybe even in the sun :smile:

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Reply 1591

Racoon

19

Hi, could some tell me do we need to know about argon dating?

Reply 1592

noseypo

1

Does anyone know the experiment/ apparatus used to test charles law??

Reply 1593

Sbarron

3

Original post by gcsestuff

I'm praying for a lovely 15 marks on fission and the nuclear reactor too. Maybe even in the sun :smile:

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Yep me too

Reply 1594

Sbarron

3

Original post by noseypo

Does anyone know the experiment/ apparatus used to test charles law??

Even better could anyone give us a model answer for this sort of question please?

Reply 1595

gcsestuff

2

Original post by Sbarron

Even better could anyone give us a model answer for this sort of question please?

2nd that

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Reply 1596

gcsestuff

2

Is this the general idea of the inversion tube experiment:

Lead spheres are heated to a certain temperature.

They are then put in a tube and the tube is rotated a certain number of time.

Due to energy loss from gravity, mgh and the total no. Of rotations we can say that mcT=mghn

Which cancels to give us c= gln/T

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Reply 1597

AR_95

21

Original post by gcsestuff

Is this the general idea of the inversion tube experiment:

Lead spheres are heated to a certain temperature.

They are then put in a tube and the tube is rotated a certain number of time.

Due to energy loss from gravity, mgh and the total no. Of rotations we can say that mcT=mghn

Which cancels to give us c= gln/T

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Think so yep. Just remember details of the experiment