You are Here: Home >< Physics

# AQA Physics PHYA4 - 20th June 2016 [Exam Discussion Thread] Watch

1. (Original post by liverpool2044)
ah okay so negatives travel in opposite direction to the positive? is this similar in electric fields?

which travel with the force and opposite the field
Yes, a negative charge moving to the right for example has to be treated as a positive charge moving to the left.

Electric field lines show you the direction a positive charge would move if it was placed in that field.
2. Is the electric field always the negative of the potential gradient?
3. How many repeated questions will there be in the MC?

Posted from TSR Mobile
4. What does it mean about the radial to non radial thing? Does someone mind drawing exactly what is required? thanks
Attached Images

5. Anyone got any tips for being fast (ish) on the multiple choice? I just did one and only answered 12.....
6. (Original post by Nikhilm)
What does it mean about the radial to non radial thing? Does someone mind drawing exactly what is required? thanks
Hmm, they are both positive point charges. Imagine when there electric fields meets, what's going to happen to the lines? Their radial pattern will change.
7. (Original post by Throor)
Anyone got any tips for being fast (ish) on the multiple choice? I just did one and only answered 12.....
Keep doing past papers, it honestly really helps with the timing.
8. (Original post by particlestudent)
Hmm, they are both positive point charges. Imagine when there electric fields meets, what's going to happen to the lines? Their radial pattern will change.
It wouldn't change to non radial though? I think they're talking about the back end of the charges but I'm not 100%, hence requesting someone to draw a diagram
9. (Original post by Nikhilm)
It wouldn't change to non radial though? I think they're talking about the back end of the charges but I'm not 100%, hence requesting someone to draw a diagram
Take a look at this diagram to give yourself an idea of what they mean. Modify that diagram to suit the magnitude of the charges they used.
Attached Images

10. (Original post by particlestudent)
Take a look at this diagram to give yourself an idea of what they mean. Modify that diagram to suit the magnitude of the charges they used.
Ah thanks!
11. (Original post by Nikhilm)
Ah thanks!
No problem .
12. Can somebody explain to me why this one is C?
13. (Original post by CD1998)
Can somebody explain to me why this one is C?
It is moving parallel to the field so it won't experience a force.

No force means no acceleration so no change in speed.
14. Can someone please help me? Q24 june 13 section A. I get the emf bit but not the direction. Thanks
Attached Images

15. (Original post by particlestudent)
Yes, a negative charge moving to the right for example has to be treated as a positive charge moving to the left.

Electric field lines show you the direction a positive charge would move if it was placed in that field.
thank youuu
16. Multiple Choice section seems ok now after 5 past papers

Posted from TSR Mobile
17. (Original post by Yo12345)
Multiple Choice section seems ok now after 5 past papers

Posted from TSR Mobile
Which papers have you done?
18. (Original post by particlestudent)
Which papers have you done?
Jan 2010 - Jan 2012 at home. Just need to do June 12 and Jan 13 tomorrow and June 2013 on Sunday. June 2014 and 15 as mocks. What about you?

Posted from TSR Mobile
19. http://prntscr.com/bhq9df

I'm failing to see why the answer isn't D. If the magnet is decelerating once it enters the coil (due to Lenz's law) surely this means that the lines of flux cut per second decreases from a given value to zero.

Edit: nvm I think I got it. I might have been getting confused with rate of change of flux linkage and simply flux linkage, i.e. the explanation is that the flux linkage rises from 0 to a value as it enters the field, creating a rate of change and thus inducing emf (causing a current reading to be displayed), but then that change stops occurring, so there's no more induced emf
20. (Original post by ¡Muy bien!)
Can someone please help me? Q24 june 13 section A. I get the emf bit but not the direction. Thanks
Magnetic flux=BA
Area which the rod moves through= length * distance covered
(where distance covered, d, equals velocity * time taken, from v=s/t)
Magnetic flux equals BLvt, emf induced equals the rate of change of flux density.
Therefore EMF=BLvt/t, the t's cancel, so the emf=BLv.

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: January 9, 2017
Today on TSR

Find help on your application here

### Motivate me!

Discussions on TSR

• Latest
• ## See more of what you like on The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

• Poll
Useful resources

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
Discussions on TSR

• Latest
• ## See more of what you like on The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

• 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