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

Can someone remember/verify this please? cheers

(1) 4.4*10TOTHE POWER OF SOMETHING electrons? (not halved answer)

(2) Was the 4 coils A (the one with the larger side?)

(3) was the last ques power heat loss something?

(4) was the mass on the scale definitely -322g? (many others have said 0 for some reason)

And finally for damping
Which box did you have to tick 1st or second? the ques wording was confusing me

Additonal ques, why would the height not reach 1.4 in real life ?
1) work done against air resistance
2) thermal energy lost as heat by the motor?

(edited 8 years ago)

Reply 4721

RemainSilent

3

Original post by CD223

It was I'm pretty sure. B was the 0.5x0.5 one.

Posted from TSR Mobile

I put A because the longer side would experience more force tand the top side would experience no force as it is parallel to to B not sure tho

Reply 4722

Lau14

11

Original post by RemainSilent

Can someone remember/verify this please? cheers

(1) 4.4*10TOTHE POWER OF SOMETHING electrons? (not halved answer)

(2) Was the 4 coils A (the one with the larger side?)

(3) was the last ques power heat loss something?

(4) was the mass on the scale definitely -322g? (many others have said 0 for some reason)

And finally for damping
Which box did you have to tick 1st or second? the ques wording was confusing me

1. yes, 2. no, 3. last multiple choice question? no, 4 yes

Damping was I believe the second box?

Reply 4723

MSB47

2

Original post by CD223

Updating MS in the first post. Any help people!?

Posted from TSR Mobile

For the emf induced dont you multiply it by the number of turns? Because I got 4.8

Reply 4724

JaySP

3

Original post by ssargithan

Anyone did emf divide by square root 2?

YES. did you get 0.13A?

Reply 4725

Kennethm

2

2b) the first bit is right

the 2nd mark is for
a positive test charge will have to do work against the field to reach a point in this field from infinity (or something to that effect.)

also wondering why 2) e) is 1560, cant remember if i got that or nah

Reply 4726

a.a.k

2

Lol the picture people in the picture on bbc website are surely doing maths you can see the pink formula bookleta

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Reply 4727

AR_95

21

Original post by CD223

Updating MS in the first post. Any help people!?

Posted from TSR Mobile

for the raising height of 1.4m thing, in practice it wouldnt go as high because energy is lost due to air resistance of the air, plus the heating effect of the current??

Reply 4728

JizzaStanger

4

Original post by CD223

Updating MS in the first post. Any help people!?

Posted from TSR Mobile

Other possible points for 1)a):

Forced oscillations:
When a periodic force (PF) is applied to a natural oscillator (NO) (Which has a natural frequency).
If PF has frequency much lower than NO, then NO oscillates with roughly same amplitude as periodic force. Small/no phase difference.
If PF has frequency much higher than NO, then NO oscillates with small amplitude. Variable phase difference and amplitude. Max amplitude when PF is pi/2 radians out of phase with NO and minimum amplitude when PF is in phase with NO.

Also in resonance, oscillations may be violent.

Reply 4729

chizz1889

5

Original post by Lau14

1. yes, 2. no, 3. last multiple choice question? no, 4 yes

Damping was I believe the second box?

It was -322, it's been on other past papers ☺️
Ignore that I read it wrong lol

Reply 4730

CD223

OP

10

Thanks!

Added.

Original post by JizzaStanger

Other possible points for 1)a):

Forced oscillations:
When a periodic force (PF) is applied to a natural oscillator (NO) (Which has a natural frequency).
If PF has frequency much lower than NO, then NO oscillates with roughly same amplitude as periodic force. Small/no phase difference.
If PF has frequency much higher than NO, then NO oscillates with small amplitude. Variable phase difference and amplitude. Max amplitude when PF is pi/2 radians out of phase with NO and minimum amplitude when PF is in phase with NO.

Also in resonance, oscillations may be violent.

Reply 4731

alex3107_

5

Can someone explain why Q20 in section A was -322g and not zero?

Reply 4732

garga

1

only AQA http://www.bbc.co.uk/news/education-33094306

Reply 4733

RemainSilent

3

At lowest in MC i got 20/25 and around 30-34ish on written (4 marks lost damping, 3 graph, 1 area under graph, 3 angle :/ , few more in written not sure if i lost 2 at potential ) would 50 be a B ?

Reply 4734

Kennethm

2

2b) the first bit is rightthe 2nd mark is fora positive test charge will have to do work against the field to reach a point in this field from infinity (or something to that effect.)also wondering why 2) e) is 1560, cant remember if i got that or nah

Reply 4735

apriori1234

8

Original post by alex3107_

Can someone explain why Q20 in section A was -322g and not zero?

The reading is zero if and only if no force acts on the magnet, because it says the balance was zeroed before the experiment.

Posted from TSR Mobile

Reply 4736

Lau14

11

Original post by RemainSilent

At lowest in MC i got 20/25 and around 30-34ish on written (4 marks lost damping, 3 graph, 1 area under graph, 3 angle :/ , few more in written not sure if i lost 2 at potential ) would 50 be a B ?

Looking at past boundaries (in the first post), 50 should most definitely be a B, possibly a high one :smile:

Reply 4737

xela238

3

Original post by otterfailure

i am so pissed i for some reason read the question about the horizontal! circle to be a vertical circle so thats at least 18 marks down the sh*tter. I don't know i don't think physics is that bad i just keep making these kind of stupid mistakes. Goodbye A/A* :frown:

Can i still do well if the unit 5 goes well?

What question are you referencing?

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Reply 4738

CD223

OP

10

Original post by Lau14

Looking at past boundaries (in the first post), 50 should most definitely be a B, possibly a high one :smile:

How did you find the paper? :smile:

Posted from TSR Mobile

Reply 4739

MSB47

2

Original post by a.a.k

Why does f become F/9 for 4R
I put 8 R

Posted from TSR Mobile

The radius of the spheres make 2R the force when in contact is 4F really and 4 divided by something gives 1/9 and that is 36 which you square root to give a total distance of 6R minus the 2R of the spheres as it asks for distance between surfaces

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

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