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

I think I may have put electromagnetic repulsion instead of force because I was thinking of the alpha particles being repelled by the nucleus so I wrote repulsion by accident instead of force -.- would that still be valid for a mark? :/

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I too put Repulsion due to positive charge :/

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Reply 3121

Disney0702

9

Original post by physics01

Guys did your paper for section b have R on the end of the code

Oooh i actually forgot to check. Did yours?

Reply 3122

Salt and Peppa

1

Original post by Jed-Singh

I did (Q=MCT)-(Q=ml) will I lose all 3 marks?

If you did it to 2 s.f. you will get 1 mark.

Reply 3123

Christina30

I think it was 0.15 m

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Reply 3124

Jed-Singh

3

Original post by Salt and Peppa

If you did it to 2 s.f. you will get 1 mark.

I calculated them both separately, then did MCT-ML to 3sf

Reply 3125

QueNNch

3

Original post by Disney0702

Oooh i actually forgot to check. Did yours?

Yes everyones paper had R on the code. Confirmed.

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Reply 3126

Disney0702

9

Original post by QueNNch

I'm sure it said "Describe an experiment..." :redface:

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You're right it did.

Reply 3127

RThornton

4

What was the answer in the section A nuclear and thermal, what happens to the rutherford scattering using different isotopes? I said it changes because if you used a hypothetical extreme with loads of neutrons, the nucleus would be much bigger and therefore more of the alpha particles path's would be affected by it

Reply 3128

Jed-Singh

3

Original post by RThornton

What was the answer in the section A nuclear and thermal, what happens to the rutherford scattering using different isotopes? I said it changes because if you used a hypothetical extreme with loads of neutrons, the nucleus would be much bigger and therefore more of the alpha particles path's would be affected by it

no change as only affected by protons and isotopes have same number of protons I put

Reply 3129

SuperMushroom

9

Original post by RThornton

What was the answer in the section A nuclear and thermal, what happens to the rutherford scattering using different isotopes? I said it changes because if you used a hypothetical extreme with loads of neutrons, the nucleus would be much bigger and therefore more of the alpha particles path's would be affected by it

Put why would you use a hypothetical model... The answer was simply no change as the overall charge on the nucleus remains the same,

You over complicated the question

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Reply 3130

Salt and Peppa

1

Original post by RThornton

What was the answer in the section A nuclear and thermal, what happens to the rutherford scattering using different isotopes? I said it changes because if you used a hypothetical extreme with loads of neutrons, the nucleus would be much bigger and therefore more of the alpha particles path's would be affected by it

Not affect
Isotopes have same number of protons but different number of neutrons
Protons would only affect the path (Can state an equation to further reinforce, I did because I didn't really know how to explain it e.g. R = Q1Q2/4piE0Ek)
Alpha particles never touch nucleus, so only affected by protons of nucleus.

(edited 8 years ago)

Reply 3131

chizz1889

5

Original post by RThornton

What was the answer in the section A nuclear and thermal, what happens to the rutherford scattering using different isotopes? I said it changes because if you used a hypothetical extreme with loads of neutrons, the nucleus would be much bigger and therefore more of the alpha particles path's would be affected by it

The nucleus won't be much bigger, adding/removing one or two neutrons will have negligible effect on the spherical volume of the nucleus. It had no effect as the charge of the gold remained the same

Reply 3132

Bowenabc

Original post by TheRAG

4.4x1011m

Did you calculate it by taking 1 AU from 2.57AU (whatever the furthest distance was)

or did you calculate it using a triangle with base 1 AU and legnth 2.57AU and take
hypotenuse?

Reply 3133

chizz1889

5

Original post by Disney0702

You're right it did.

Yeah but it said you didn't need to include any apparatus details so it was basically just describing the measurements/calculations involved in the experiment

Reply 3134

chizz1889

5

Original post by Bowenabc

Did you calculate it by taking 1 AU from 2.57AU (whatever the furthest distance was)

or did you calculate it using a triangle with base 1 AU and legnth 2.57AU and take
hypotenuse?

You had to add 1 AU to 2.57AU and convert to metres

Reply 3135

lad123

1

Original post by chizz1889

Yeah but it said you didn't need to include any apparatus details so it was basically just describing the measurements/calculations involved in the experiment

So you could literally just say, measure pressure at different temperatures at constant volume, where line crosses x axis blah, when T = 0 pressure is 0 as ke = 0 so v = 0, so no particles collide with wall.

Reply 3136

Bowenabc

Original post by chizz1889

You had to add 1 AU to 2.57AU and convert to metres

But how would you be able to see Vegas if it was on the otherside of the sun?
And what was your subsequent answers for the angle subtended by Vegas, and what did you write for discuss level of details the telescope can see?

Do you also remember how many marks these questions were worth?