The Student Room Group

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

Scroll to see replies

Original post by CD223
Thank you so much! That's great! Which parts of PHYA4 do you find hardest? And how do you prepare?:smile:


Posted from TSR Mobile


I'm terrible at exam technique, I still haven't found my optimal revision manner yet, and so I do a mix of creating these revision sheets and past papers :biggrin:

I've found (In Unit 1 as well) that I struggle with anything to do with electricity, probably because I'm not really sure I understand it, but OK with the rest I think :P
Original post by KeithHayward
Anyone got any tips for improving timing other than practice?


I do the exam backwards. I (usually) start with the 6-mark question to get it out of the way, then do the main written paper, and then do the multiple choice at the end, because then, if you find you're running out of time on the last few multi-choice, you can just pick an answer, since you'll have a 25% chance of being right, and they're only worth 1 mark each anyway, so not too big a loss when compared to running out of time for the 6-marker. :biggrin:
Reply 82
Just had a mock EMPA on capacitors and the oscillations of ball bearings and rulers from June 2012. That was...odd.


Posted from TSR Mobile
Original post by SeanWinder1997
I do the exam backwards. I (usually) start with the 6-mark question to get it out of the way, then do the main written paper, and then do the multiple choice at the end, because then, if you find you're running out of time on the last few multi-choice, you can just pick an answer, since you'll have a 25% chance of being right, and they're only worth 1 mark each anyway, so not too big a loss when compared to running out of time for the 6-marker. :biggrin:


Smart! I'd never thought of doing the 6 marker first. I'll try this out in my next mock season and see how it plays out, thanks :smile:
Reply 84
Original post by KeithHayward
Smart! I'd never thought of doing the 6 marker first. I'll try this out in my next mock season and see how it plays out, thanks :smile:


The 6 marker is always good to at least look at to start with and then you can sort of think about it in the back of your brain if it's a tough one :smile: if you like the look of the question it gives you a bit of confidence to start the exam with too :smile:

Posted from TSR Mobile
Original post by _Caz_
The 6 marker is always good to at least look at to start with and then you can sort of think about it in the back of your brain if it's a tough one :smile: if you like the look of the question it gives you a bit of confidence to start the exam with too :smile:

Posted from TSR Mobile


How are you going about doing past papers? Are you timing yourself and being really strict or are do you just work through questions at your own pace. I know this will vary massively depending on who you are, but it would be nice to get another students perspective... :cool::colondollar:
Reply 86
Original post by KeithHayward
How are you going about doing past papers? Are you timing yourself and being really strict or are do you just work through questions at your own pace. I know this will vary massively depending on who you are, but it would be nice to get another students perspective... :cool::colondollar:


We get given tests every 3 weeks at college (which just gives us a load of unnecessary stress but nvm) so I've been practising past papers by topic rather than date if that makes any sense. There aren't that many papers so I'm not sure what I'm gonna practise on to prepare for the exams :/ how is it going for you?

Posted from TSR Mobile
Reply 87
Could anyone kindly explain the whole back emf thing to me again please?


Posted from TSR Mobile
Original post by _Caz_
We get given tests every 3 weeks at college (which just gives us a load of unnecessary stress but nvm) so I've been practising past papers by topic rather than date if that makes any sense. There aren't that many papers so I'm not sure what I'm gonna practise on to prepare for the exams :/ how is it going for you?

Posted from TSR Mobile


So do we! My sixth form gives us topic tests every two weeks on what we've been learning i.e. the next test is on chapter 11. It's going well, I might just do the exam style q's in the AQA textbook when I come to finish all of the past papers :rolleyes:
Original post by CD223
Could anyone kindly explain the whole back emf thing to me again please?


Posted from TSR Mobile


What is it specifically that you're not sure of?
Reply 90
Original post by KeithHayward
What is it specifically that you're not sure of?


Just what it is, and essentially all the features we need to know about it. All I understand of it is that it's an emf that opposes the direction of the one you're trying to generate and it varies depending on the load? I know very little haha.


Posted from TSR Mobile
Original post by CD223
Just what it is, and essentially all the features we need to know about it. All I understand of it is that it's an emf that opposes the direction of the one you're trying to generate and it varies depending on the load? I know very little haha.


Posted from TSR Mobile


Put simply, when a motor coil spins in a magnetic field, current is flowing (phd here I come).

Back emf is the emf that is induced in the spinning coil which tries to oppose the flow of current.

If the speed of rotation of the coil is low, this means that the back emf must also be low, so the current flowing will be high as theres no back emf to oppose its flow, and the other way round too.

This is my understanding, i'm 98% sure its correct. If anyone spots anything wrong please point it out but I think its a pretty tight summary of what we need to know...
Reply 92
Original post by KeithHayward
Put simply, when a motor coil spins in a magnetic field, current is flowing (phd here I come).

Back emf is the emf that is induced in the spinning coil which tries to oppose the flow of current.

If the speed of rotation of the coil is low, this means that the back emf must also be low, so the current flowing will be high as theres no back emf to oppose its flow, and the other way round too.

This is my understanding, i'm 98% sure its correct. If anyone spots anything wrong please point it out but I think its a pretty tight summary of what we need to know...


Ah that makes sense, thanks!


Posted from TSR Mobile
Original post by CD223
Ah that makes sense, thanks!


Posted from TSR Mobile


No worries :cool:
Reply 94
Original post by KeithHayward
No worries :cool:


What grade are you aiming for?


Posted from TSR Mobile
Original post by CD223
What grade are you aiming for?


Posted from TSR Mobile


The highest I can get :colone::wink:- I've heard its very easy to miss out on the A* in physics so idk. How about you?
Reply 96
Original post by KeithHayward
Put simply, when a motor coil spins in a magnetic field, current is flowing (phd here I come).

Back emf is the emf that is induced in the spinning coil which tries to oppose the flow of current.

If the speed of rotation of the coil is low, this means that the back emf must also be low, so the current flowing will be high as theres no back emf to oppose its flow, and the other way round too.

This is my understanding, i'm 98% sure its correct. If anyone spots anything wrong please point it out but I think its a pretty tight summary of what we need to know...


Is backwards emf to do with Lenz's Law?
Original post by JaySP
Is backwards emf to do with Lenz's Law?


I think it is. Has anyone seen any questions that mention it?


Posted from TSR Mobile
Reply 98
Original post by KeithHayward
The highest I can get :colone::wink:- I've heard its very easy to miss out on the A* in physics so idk. How about you?


Yeah I'm aiming for an A because the chances of me getting an A* are so slim. Only scraped an A in our recent mock and I find the empas hard haha.


Posted from TSR Mobile
Reply 99
Original post by KeithHayward
I think it is. Has anyone seen any questions that mention it?


Posted from TSR Mobile


I've not which is why I originally flagged it up as there aren't any model exam answers :s-smilie:


Posted from TSR Mobile

Quick Reply

Latest

Trending

Trending