AQA A Level Physics Paper 2 7408/2 - 08 June 2018 [Exam Discussion]

Hey guys,

I've done all the Unit 4A and B , and thermal unit 5 past papers and I've scored pretty well on the new papers.

However, in my Paper 1, I really messed up even though I think I am quite good at physics!!

Any tips to stay calm :frown:

clear headed?

I messed up too, most likely got 10 marks in the whole paper that's how much I messed up, thought i was good at physics too! :frown:

left out two whole pages unanswered!

If knowing someone else is just as f**ked as you makes you calmer then hi nice to meet you! :biggrin:

Reply 81

Amanzhol

19

In the magnetic fields part of the spec it says we need to know the "direction of force on positive and negative charged particles".

I'm probably being really thick here but could someone explain the difference in the direction of the force for +/- charged particles? Is it something to do with the left hand rule?

Reply 82

G.Y

16

Why do the reading on scales show a positive value when force on current-carrying wire in between magnets is upwards?

Reply 83

jamesmessenger

4

Original post by BTAnonymous

we haven't even done paper 2.

I think that was the point :smile:

Reply 84

Madtin

5

Original post by Amanzhol

In the magnetic fields part of the spec it says we need to know the "direction of force on positive and negative charged particles".

I'm probably being really thick here but could someone explain the difference in the direction of the force for +/- charged particles? Is it something to do with the left hand rule?

Left hand rule tells you what happens for a positive charge, so if for example it gives you an electron, either use the left hand rule and just take the opposite of whatever thing you need, or use the right hand rule as normal

Reply 85

humhallelujah

7

Original post by Amanzhol

In the magnetic fields part of the spec it says we need to know the "direction of force on positive and negative charged particles".

I'm probably being really thick here but could someone explain the difference in the direction of the force for +/- charged particles? Is it something to do with the left hand rule?

Think it's that the force acts in opposite directions on opposite charges, and that the direction of current for the left hand rule is the direction of motion of a positive charge, and the opposite direction to the direction of motion of a negative charge

Reply 86

ZEBcobb

3

Original post by G.Y

Well that's not true because there was a question that asked you to calculate distance when v = 0 between 2 opposite charges.

Can you send the question please?

Reply 87

ZEBcobb

3

Original post by G.Y

Why do the reading on scales show a positive value when force on current-carrying wire in between magnets is upwards?

Newtons 3rd- every force a]has equal and opposite reaction

Reply 88

G.Y

16

Original post by ZEBcobb

Newtons 3rd- every force a]has equal and opposite reaction

So if the force was downwards would the reading be the same?

Reply 89

ZEBcobb

3

Original post by G.Y

So if the force was downwards would the reading be the same?

but in opposite direction

Reply 90

wantodothebest

11

Original post by BTAnonymous

just don't skip questions so easily. Sometimes it's better to spend another minute thinking because it then clicks and then you fly away and solve the question. If you move on too quickly you can lose your train of thought. however, you also need to realise when to move on.

physics has 2 hours for an 85 mark paper for a reason; because it's difficult. chemistry for example is 105 marks but is till 2 hours for the same exam board so it just shows they expect you to spend a bit more time thinking.

Really solid advice, thank you

I would rep you again but it wont let me because i dont give rep to anyone else

Reply 91

BTAnonymous

22

Original post by wantodothebest

Really solid advice, thank you

I would rep you again but it wont let me because i dont give rep to anyone else

np.

it can be really tempting to move on quickly because you're so used to doing the easy past papers where you had so much time to check your answers which is why you might panic.

anyway, good luck tomorrow :smile:

Reply 92

G.Y

16

Original post by ZEBcobb

but in opposite direction

Can a scale have a negative reading though? I don’t think so

Reply 93

ZEBcobb

3

Original post by G.Y

Can a scale have a negative reading though? I don’t think so

depends if its been zeroed with an object on it... if so then when the object is removed the reading is negative

Reply 94

RishiReload21

Original post by blue bear

I messed up too, most likely got 10 marks in the whole paper that's how much I messed up, thought i was good at physics too! :frown:

left out two whole pages unanswered!

If knowing someone else is just as f**ked as you makes you calmer then hi nice to meet you! :biggrin:

I am also in the same predicament, I thought paper 1 was incredibly tough, I thought I did quite poorly even though I would consider myself to be okay at physics. I did most of the past papers, from OCR even but it didn't help :/
However positive thinking, let's recover in the exam tomorrow!

Reply 95

username2748677

12

For a helium-3 nucleus and a helium-4 nucleus to fuse they need to be separated by no more than 3.5 × 10–15 m. (i) Calculate the minimum total kinetic energy of the nuclei required for them to reach a separation of 3.5 × 10–15 m.

does anyone fancy doing this question???

Reply 96

username2057011

13

Original post by EA7_

For a helium-3 nucleus and a helium-4 nucleus to fuse they need to be separated by no more than 3.5 × 10–15 m. (i) Calculate the minimum total kinetic energy of the nuclei required for them to reach a separation of 3.5 × 10–15 m.

does anyone fancy doing this question???

w=q. change in v

look up v quation and use it to multiply by the charge

Reply 97

ZEBcobb

3

Original post by EA7_

For a helium-3 nucleus and a helium-4 nucleus to fuse they need to be separated by no more than 3.5 × 10–15 m. (i) Calculate the minimum total kinetic energy of the nuclei required for them to reach a separation of 3.5 × 10–15 m.

does anyone fancy doing this question???

I believe you need to use coulombs law and set it = to the KE. (maybe x distance to make it work done)