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

Reply 1580

Georgia xx

would anyone have the question paper, for nuclear or astrophysics? :smile:

plus is there an unofficial markscheme for astrophysics?

Reply 1581

iluvmaths

5

for maxwells question, i said that the epsilon was a property of an electric field and mu was a property of a magnetic field. also, multyplying the two is like dotting them, hence he concluded that they must be perpendicular and that as this also defined EM waves, light must be a part of the EM spectrum.

Reply 1582

ksryiovulna356

Most of the paper seemed really straightforeward. Put that 6 marker absolutly floored me. I knew everything on Rutherford, and NOTHING on electron diffraction. Anybody think there's a chance of scrounging some marks from Rutherford? I basically wrote everything there is to know on it but nothing on ED. :/

Also, what kind of numbers were people getting on the first question?

Oh, and for anyone who did astro, when it asked us to clasify the star, was it an A class star? And what were the secondary absorbtion lines?

Reply 1583

iluvmaths

5

and hats off to those who warned me about hertz yesterday!

Reply 1584

Rach3ch

Original post by QuangHa

Finally found someone :biggrin:

The paper was alright, I think they have gone easy on the engine and the cycle thingy. What do you get for indicated Power?

I cant really remember but i remember counting the squares and got 20 squares so, 20*500*something! What did you get? If it sounds familiar i might remember :smile:

i think i remember getting 100++kW something like that.. 160 something around 100-160 you?

Reply 1585

aware?

Original post by James24993

Most of the paper seemed really straightforeward. Put that 6 marker absolutly floored me. I knew everything on Rutherford, and NOTHING on electron diffraction. Anybody think there's a chance of scrounging some marks from Rutherford? I basically wrote everything there is to know on it but nothing on ED. :/

Also, what kind of numbers were people getting on the first question?

Oh, and for anyone who did astro, when it asked us to clasify the star, was it an A class star? And what were the secondary absorbtion lines?

for astro, B and helium is what i put

Reply 1586

Ps3SuperSRG

13

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

Reply 1587

OT93

Original post by bozdag

Here is my mark scheme for section A.
It only includes calculations though. None of the worded questions are included.
And it may contain mistakes, so don't just accept the answers if they look wrong.
At the same time though, don't just bash my answers if yours are different. Check the working out first.

Hi for question 3 bii) (working out the activity) can I ask why did you divide by 4 times ten to the minus 3?

Thanks (not bashing, just want to understand your logic) :smile:

Reply 1588

ksryiovulna356

Original post by aware?

for astro, B and helium is what i put

I put A and helium D:

Reply 1589

Rach3ch

Original post by LeeM1

Should both get the mark! For the output power of that rotating blade did you add the torque from the first part to the frictional torque? I think the total torque was 6.

I remember getting total torque as 6!!

Reply 1590

Georgia xx

Original post by James24993

Most of the paper seemed really straightforeward. Put that 6 marker absolutly floored me. I knew everything on Rutherford, and NOTHING on electron diffraction. Anybody think there's a chance of scrounging some marks from Rutherford? I basically wrote everything there is to know on it but nothing on ED. :/

Also, what kind of numbers were people getting on the first question?

Oh, and for anyone who did astro, when it asked us to clasify the star, was it an A class star? And what were the secondary absorbtion lines?

i got a class B star as it was a temp of 22000K which is a B star, so i put helium as the second absorbtion thing :P i could be wrong of course but i hope this helps :smile:

Reply 1591

Amirrryy

1

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 :frown:

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. :frown:

may have cost me lose my uni place by coming short by like 11 UMS. **** aqa

(edited 11 years ago)

Reply 1592

ksryiovulna356

Original post by Georgia xx

i got a class B star as it was a temp of 22000K which is a B star, so i put helium as the second absorbtion thing :P i could be wrong of course but i hope this helps :smile:

No I'm fairly sure I'm wrong, as I put A :frown:

Oh, well. At least I put helium. :biggrin:

Reply 1593

OT93

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

Reply 1594

Insanity514

15

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

There wasn't one.
Only place where you could have mentioned it was the 6 marker on nuclear where
1/2mv^2=Qq/4piepsilon0r, and you could have mentioned that all alpha particles need to be of same speed and hence same kinetic energy.

(edited 11 years ago)

Reply 1595

Rach3ch

Original post by Rach3ch

I cant really remember but i remember counting the squares and got 20 squares so, 20*500*something! What did you get? If it sounds familiar i might remember :smile:

i think i remember getting 100++kW something like that.. 160 something around 100-160 you?

Actually wait 68kW sounds familiar. the 100+ might be the next question.

Reply 1596

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:

Reply 1597

AreebWithaHat

18

Original post by OT93

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

98 db?

Reply 1598

bozdag

10

Original post by OT93

Hi for question 3 bii) (working out the activity) can I ask why did you divide by 4 times ten to the minus 3?

Thanks (not bashing, just want to understand your logic) :smile:

That was the ratio we worked out between the count rate and activity. But since we're working out activity we need to divide it instead of multiplying.

Reply 1599

Ps3SuperSRG

13

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:

Light on hills(less clouds),x ray in space(x ray absorbed in atmosphere so in space = non lost/more detected),radio can be everywhere as passes straight through atmosphere.

Resolution of radio v.poor due to long wavelength.
Solution have groups of radio telescopes that act like 1 big one;more collecting power. :smile:

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

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

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