Turn on thread page Beta
 You are Here: Home >< Physics

# AQA Physics PHYA4 - Thursday 11th June 2015 [Exam Discussion Thread] watch

1. (Original post by Disney0702)
Can someone please explain Q1(b)(iii) from Jun '12 Section B.

I do not understand the second step in the mark scheme.

Thank you in advance.
Uploaded a solution to that a few days ago. Here's the link:

http://www.thestudentroom.co.uk/show...=#post56336639

Let me know if you need any help/can't read my messy handwriting
2. (Original post by _Caz_)
We have the same calculators haha Ngl though, I hate my graphics one, only use it in further maths when I have to. It takes like three buttons to delete one line of working! (also it scares me with how much it can do)

The casio fx-911ES plus is great though!
Lol yeah, and it has a backlight! For when you're furiously calculating at night

3. Can someone give me a hint on what to do please

Posted from TSR Mobile
4. (Original post by Protoxylic)
Lol yeah, and it has a backlight! For when you're furiously calculating at night
casio knows we maths people too well :'D
5. (Original post by gcsestuff)
Can someone give me a hint on what to do pleasePosted from TSR Mobile
This happens when they are first at a 2pi phase difference. The faster one (P) will therefore have done one more complete oscillation than the slower one (Q), so if we assume Q has done n complete oscillations we have 1.9(n+1)=1.95n or 1.9=0.05n, i.e. Q does n=38 oscillations.
6. 3000+ posts! You guys really do love physics

Posted from TSR Mobile
7. (Original post by gcsestuff)

Can someone give me a hint on what to do please

Posted from TSR Mobile
I struggle with these questions too. There is a way of doing them though and I don't understand it but it works.

find the difference between the two time periods.

If it wants the number of oscillations of the one with the longer time period, divide the value of the shorter time period by the difference between the two time periods.

If it wants the number of oscillations of the one with the shorter time period, divide the value of the longer time period by the difference between the two time periods.

I know this wasn't exactly what you were looking for and I really struggle to get my head around these too but that method works every time
8. (Original post by tawaz1997)
The top one is 'B'.Electromagnetic induction only happens, in this case, when the magnitude or direction of flux changes. When the current is increasing, there's em induction going on, when its constant nothing happens,

Sorry I'm bad at explaining...haha

The other one...come on, that's pretty straight forward
GMm/r^2 = mv^2/r where M is the mass of the sun and m the mass of the earth,r is the distance, = radius of earth + orbital radius + radius of the sun

Posted from TSR Mobile
I think you're very wrong for the first one and I definitely think it is 'C'. My reasoning is that if you go to a maximum value of current then switch it off, then that will be the greatest change in the coil X's magnetic field produced since it goes to a maxima to nothing. Therefore, the other coil will cut the coil 'X' field lines at the fastest rate for this event out of all the other events listed and hence that will induce highest emf for other coil and thus highest reading on the ammeter.
9. (Original post by _Caz_)
I struggle with these questions too. There is a way of doing them though and I don't understand it but it works.

find the difference between the two time periods.

If it wants the number of oscillations of the one with the longer time period, divide the value of the shorter time period by the difference between the two time periods.

If it wants the number of oscillations of the one with the shorter time period, divide the value of the longer time period by the difference between the two time periods.

I know this wasn't exactly what you were looking for and I really struggle to get my head around these too but that method works every time
Mate that's perfect thanks! Hope it comes up now!!!

Posted from TSR Mobile
10. (Original post by adil1231)
I think you're very wrong for the first one and I definitely think it is 'C'. My reasoning is that if you go to a maximum value of current then switch it off, then that will be the greatest change in the coil X's magnetic field produced since it goes to a maxima to nothing. Therefore, the other coil will cut the coil 'X' field lines at the fastest rate for this event out of all the other events listed and hence that will induce highest emf for other coil and thus highest reading on the ammeter.
Yeah that's true.

Posted from TSR Mobile
11. Cd did you ask your teacher about the gravity question regarding orbits?

Posted from TSR Mobile
12. Everyone's saying the biology unit 4 paper contained all unit 1 and 2 questions. I hope that won't happen to us, but then I guess that's what's gonna happen over the coming years with one paper sat at the very end

Posted from TSR Mobile
13. (Original post by _Caz_)
I struggle with these questions too. There is a way of doing them though and I don't understand it but it works.

find the difference between the two time periods.

If it wants the number of oscillations of the one with the longer time period, divide the value of the shorter time period by the difference between the two time periods.

If it wants the number of oscillations of the one with the shorter time period, divide the value of the longer time period by the difference between the two time periods.

I know this wasn't exactly what you were looking for and I really struggle to get my head around these too but that method works every time
There was a difference of 0.1, beween T1 = 2 and T2 = 1.9, but the answer was 38 not 19, whY?
14. (Original post by gcsestuff)
Cd did you ask your teacher about the gravity question regarding orbits?

Posted from TSR Mobile
Yeah only just got a reply today!

"Radius" means use that figure. "Height" means add the radius to the distance given.

Posted from TSR Mobile
15. (Original post by AR_95)
There was a difference of 0.1, beween T1 = 2 and T2 = 1.9, but the answer was 38 not 19, whY?
2 doesn't go into 19, so it must be doubled
16. Does anyone have any notes specifically for the wordy, 6 mark questions? Any help is much appreciated lol
17. (Original post by adil1231)
I think you're very wrong for the first one and I definitely think it is 'C'. My reasoning is that if you go to a maximum value of current then switch it off, then that will be the greatest change in the coil X's magnetic field produced since it goes to a maxima to nothing. Therefore, the other coil will cut the coil 'X' field lines at the fastest rate for this event out of all the other events listed and hence that will induce highest emf for other coil and thus highest reading on the ammeter.
Yeah, actually you're right. But man you can't be going around telling people they are 'very wrong', the exam is in 3 days and my confidence has just gone from 100 to 0...haha
18. (Original post by gcsestuff)
Everyone's saying the biology unit 4 paper contained all unit 1 and 2 questions. I hope that won't happen to us, but then I guess that's what's gonna happen over the coming years with one paper sat at the very end

Posted from TSR Mobile
Biology do have a very big emphasis on continuing to know unit 1/2 stuff I think though! While unit 4 of physics must contain some content from last year, it's usually in a simple way for 1-2 marks and often on the data sheet (eg. knowing that power loss due to resistance is proportional to current squared - P = I2R is an AS formula).
19. (Original post by CD223)
Yeah only just got a reply today!

"Radius" means use that figure. "Height" means add the radius to the distance given.

Posted from TSR Mobile
That's good thanks man!!

Posted from TSR Mobile
20. (Original post by _Caz_)
Uploaded a solution to that a few days ago. Here's the link:

http://www.thestudentroom.co.uk/show...=#post56336639

Let me know if you need any help/can't read my messy handwriting
Ah thank you very much

I have just one question.

Does impulse of an object have weight?
I'm inferring this from the second step in your solutio.

Turn on thread page Beta

### Related university courses

TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Updated: February 22, 2016
Today on TSR

### Exam Jam 2018

Join thousands of students this half term

Poll
Useful resources

## Make your revision easier

Can you help? Study help unanswered threadsStudy Help rules and posting guidelinesLaTex guide for writing equations on TSR

## Groups associated with this forum:

View associated groups

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE