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AQA Physics A - PHYA5 (18/06/12) - Exam thread

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Reply 1600

Red Richie

just to check, it was 6 beta particles wasn't it for that one mark question?

Reply 1601

ksryiovulna356

Original post by Georgia xx

for the astorphysics 6 marker, how did everyone find it? as i didnt really like it as we'd learnt practically nothing on other telescope types :s-smilie:

what sort of points did people make, as i want to see if i put the same sort of thing? :smile:

-Optical telescopes
-Light is blocked out by dust and clouds, light pollution inerferes with viewing.
-Should be placed in dry, remote high up areas, preferably on a mountaintop.
-Short wavelengths so can be built relitively small.

-Radio
-Not affected by atmosphere or polution, can be placed anywhere on Earth.
-However some wavebands are used commercially, so to get the full wavebands, the telescope would have to be placed in space, e.g. the moon.
-Longer wavelengths so worse resolution. To get around this, multiple are built and linked up together.

-Gamma
-Completely blocked out by atmosphere. Must aboce atmosphere in low orbit.
-Good resolution, so can be small.

Reply 1602

aware?

Original post by Red Richie

just to check, it was 6 beta particles wasn't it for that one mark question?

yes

Reply 1603

ksryiovulna356

Original post by Red Richie

just to check, it was 6 beta particles wasn't it for that one mark question?

That's what I got. :smile:

Reply 1604

Hulksmash

Here's hoping physics admission tutors read your personal statement, speak to your refs and look beyond a slight mishap in one of your grades!!

Reply 1605

LewisS911

For Medical, did anybody get 116Db for the drill question? :s-smilie:

Reply 1606

LewisS911

And Also, Will I get marked down for putting the unti bq instead of Bq?

Reply 1607

ksryiovulna356

Original post by LewisS911

And Also, Will I get marked down for putting the unti bq instead of Bq?

That would have to be an A-hole examiner for that to happen. I seriously doubt it.

Reply 1608

Georgia xx

Original post by James24993

aww thankyou, this has put my mind at rest a bit as thats basically what i talked about :smile:

however instead of gamma ones could i have talked about uv telescopes? as thats what i did :P

Reply 1609

Hulksmash

Original post by James24993

That would have to be an A-hole examiner for that to happen. I seriously doubt it.

Hopefully not. Damn you becquerel, I mean Becquerel!

Reply 1610

Insanity514

Original post by Georgia xx

for the astorphysics 6 marker, how did everyone find it? as i didnt really like it as we'd learnt practically nothing on other telescope types :s-smilie:

what sort of points did people make, as i want to see if i put the same sort of thing? :smile:

Radio
Large parabolic mesh dish, placed on ground in area of little human interference. Microwaves pass through atmosphere.

IR
High above sea level on mountains as IR can be absorbed by water vapour. Cool place so little interference by infrared. Small so less of it's own IR affects it (not sure if that's accurate).

UV
Space, UV absorbed by water vapour. Light and small so takes less energy to transfer to space=less money used to get it up there. Also small so less chance of needing repair.

Reply 1611

ksryiovulna356

For atrophyisics, what did people put for the question asking how it's possible for quasars to be discovered? I basically put "They're bright" but I thought that was a bit...blunt.

Reply 1612

Implication

Original post by Ps3SuperSRG

Some people have said something about a kinetic energy question. I don't remember doing one. Was it a question on section b? ( i did astrophysics btw)

This was posted from The Student Room's Android App on my GT-I9100

Kinetic energy question was special relativity (turning points in physics), so you're alright :tongue:

Reply 1613

Reminisce

Original post by Insanity514

UV is absorbed by ozone hence most UV telescopes are in space because ozone is higher up than water vapour.

Reply 1614

Implication

...and some people say that all A-levels are just as difficult. Laughable. I've never sat a harder paper in my life.

Reply 1615

savage903

Original post by OT93

For anyone doing the medical physics section what did they get for 2b) (the intensity level of the drill)?

98dB

Reply 1616

Insanity514

Original post by Reminisce

UV is absorbed by ozone hence most UV telescopes are in space because ozone is higher up than water vapour.

ahh right. Let's hope the examiner overlooks that!

Reply 1617

Amirrryy

For turning points anyone, this is what i remember from what i put. Definitely have mistakes but feel free to add answers correct etc.

1) the electron experiences a vertical force causing to have a vertical acceleration in a parabolic path towards the positive plate since it was negatively charged. the horizonatal component of velocity remains the same throughout its time in the field but the vertical component of velocity continues increasing until it leaves the field at which point it continues to move in a straight path

2) got this wrong i said increase B according to the formula r = mv/Bq inverse proportional. I think the correct answer is that decrease it cos the magnetic field is acting downwards in the same direction as the force due to the electric field smthng like that.

3) Binding energy is the energy needed to split a nucleus into its constituent nucleons

4) got the binding energy q wrong i just did lambda = h/mv which is wrong cos u have to do m=m(0)*gamma would i get any marks?

5)E = hf which u work out f from lambda

6) the last one on relativity asking for i got wrong, i used v = f*lambda to work out speed and then subbed it into 1/2mv^2

7) emf is induced as as the radio waves cut through the magnetic field lines of the loop causing a change in magnetic flux and hence an emf is induced as whenever there is a change in magnetic flux an emf is induced. anything needed to be added or would i get all the marks? :L

8) the field lines are parallel to the radio waves hence no change in magnetic flux (forgot to say polarised) how many marks was this?

9) two sources of radiation 1-cosmic radiation 2-plants

10) michelson morely experiment- there was fringe shift as there was time delay for when the two reflected beams met at the point of the beam splitter causing inteference shift.

11) i said they predicted that the speed of light varies in free space and that all life and electro magnetic waves travel through a substance know as ether. In other words, they were trying to prove absolute motion" etc

12) conclusions: no absolute motion, ether does not exist

13) 6 marker
wave propertY: young's double slit experiment which showed that diffracted wave fronts from the slits interfered constructively where the phase difference was a whole numbe creating maximas (bright fringes) and minimas where the phase difference was a whole number and half a wavelength (dark fringes) both interference and diffraction are wave properties
Particle like behaviour: photo electric effect. wave theory cannot explain the notion of a threshold frequency, and instananeous emission of electrons from the surface as it states that any light can cause electrons to gain enough energy to escape the surface of a metal over time independent of wavelength frequency etc but we know this isnt true as only certain wavelengths of light can provide this energy etc.

thats what i remember. please add how many marks these questions were if you know and feel free to compare edit etc. hope this helps.
overall a hard paper, section A has brought me down significantly. may have cost me lose my uni place by coming short by like 11 UMS. **** aqa

Reply 1618

bozzers

Original post by number23

what were the questions?

1-electron deflection
2-
3-was that wave particle duality?
4- michelson moreley

also, what was the last question on section a?

:smile:

2 was the EM waves one...the last one on A was the nuclear radius one I think