AQA Physics PHYA5 - Thursday 18th June 2015 [Exam Discussion Thread]

Reply 1980

2

Original post

by gcsestuff

What's the tutor is turning points 6 on your tabs can j just ask

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http://www.antonine-education.co.uk/Pages/Physics_5_Options/Turning_points/TP_06/turning_points_6.htm

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Reply 1981

EconFan_73

3

Anyone know how to do 4b on last year's Astrophysics paper?

Basically says distance to stars measured using angle of parallax method to a precision of 0.002 arc seconds. Calculate the maximum distance measurable?

Mark scheme shows use of d=1/p....?

Reply 1982

Klaxoii

2

Original post

by gcsestuff

What's the tutor is turning points 6 on your tabs can j just ask

Posted from TSR Mobile

Also, I found this whilst procrastinating on reddit, and it helped me understand slightly better what actually happens

http://www.reddit.com/r/explainlikeimfive/comments/j44uq/how_does_time_dilation_work_why_should_you_age/c28z810

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Reply 1983

CD223

OP

10

Original post

by EconFan_73

Anyone know how to do 4b on last year's Astrophysics paper?

Basically says distance to stars measured using angle of parallax method to a precision of 0.002 arc seconds. Calculate the maximum distance measurable?

Mark scheme shows use of d=1/p....?

$[br]d = \dfrac{1}{p}[br]$

This equation relates the maximum distance, d, measurable (the precision) of a telescope to the parallax angle it is capable of resolving, p.

Subbing in the numbers gives:

$[br]d = \dfrac{1}{0.002} = 500 pc[br]$

As it asks for the distance in metres,

$[br]d = 500 \times 3.08 \times 10^{16}m[br]$

$[br]\therefore d = 2 \times 10^{19}m\ \text{(1 sf)}[br]$

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Reply 1984

MSB47

2

Original post

by Exams12343

Can someone help explain Q 2b on the june 2011 paper please?

Nuclear and thermal or astro?

Reply 1985

gcsestuff

2

Milikans outcome-

Discovered the charges of loads of masses.

Realised that all charges where n* 1.6*10^19

That must mean that n was the number of a certain charge

This was to be discovered ad the charge of the electron

Am I right?

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Reply 1986

Disney0702

9

Guys I know this is a dumb question but what does count rate actually mean?

Reply 1987

CD223

OP

10

Original post

by Disney0702

Guys I know this is a dumb question but what does count rate actually mean?

Not a dumb question!

The number of sparks/detections per unit time for a particular detector placed at a certain distance away from a radioactive source.

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Reply 1988

CD223

OP

10

Is it true that the binding energy released is shared amongst products in the fraction of their masses over the total mass?

I read this which confused me:

ImageUploadedByStudent Room1434540073.308046.jpg

ImageUploadedByStudent Room1434540073.308046.jpg

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Reply 1989

johnh545

7

I need help with this question.
i dont really understand what it means by 1 in 400 detected on the facing surface of the detector.
were told earlier in the question that the detector has area 1.5x10^-3 and the count rate is 0.62

Picture3.png33.1KB

Reply 1990

johnh545

7

Original post

by CD223

Is it true that the binding energy released is shared amongst products in the fraction of their masses over the total mass?

I read this which confused me:

ImageUploadedByStudent Room1434540073.308046.jpg

Posted from TSR Mobile

energy released is equal to the total change in binding energy.
I hadnt read anything about the way the energy is divided up, but we know momentum has to be conserved so the fission fragments will have the energy divided up so that the momentum remains constant

Reply 1991

CD223

OP

10

Original post

by johnh545

energy released is equal to the total change in binding energy.
I hadnt read anything about the way the energy is divided up, but we know momentum has to be conserved so the fission fragments will have the energy divided up so that the momentum remains constant

I see. So those with lower mass will have greater velocity and hence a greater share of the total energy, as it depends on v^2?

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Reply 1992

Disney0702

9

Original post

by CD223

Not a dumb question!

The number of sparks/detections per unit time for a particular detector placed at a certain distance away from a radioactive source.

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Thank you very much, I usually get confused about that :smile:

Reply 1993

CD223

OP

10

Original post

by Disney0702

Thank you very much, I usually get confused about that :smile:

No worries :smile:

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Reply 1994

johnh545

7

Original post

by CD223

I see. So those with lower mass will have greater velocity and hence a greater share of the total energy, as it depends on v^2?

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exactly

Reply 1995

frankiejayx

2

Could anyone explain what we need to know of the parallax angle?

Reply 1996

EconFan_73

3

Original post

by CD223

*

Thanks CD223. I understand how to get the answer once you know that d=1/p, it's just I had never seen that before anywhere, neither in the textbook nor spec notes online. At least I'll know it now if it comes up tomorrow.

P.s Cheers for your notes in the op, was useful to have a quick read through as there's little bits in the Nelson Thornes book not covered in the CGP one :smile:

Reply 1997

Star Light

14

Original post

by you-only-live-once

anyone doing medical option?

Yeah I am

it's annoying, every past paper has some different facts which you needed to know, most of which aren't in my textbook or notes -.- just going through loads of old-spec medical papers at the moment...

Reply 1998

Master Sam

1

http://filestore.aqa.org.uk/subjects/AQA-PHYA51-QP-JUN14.PDF

hey guys can anyone explain why the markscheme doesnt take the binding energy of neutrons into account in Q 1b (ii) ? confused :frown:

Reply 1999

you-only-live-once

2

Original post

by Star Light

Yeah I am

it's annoying, every past paper has some different facts which you needed to know, most of which aren't in my textbook or notes -.- just going through loads of old-spec medical papers at the moment...

Yes i know! what do you think will be the 6 marker? :smile:

AQA Physics PHYA5 - Thursday 18th June 2015 [Exam Discussion Thread]

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