PHYA5 ~ 20th June 2013 ~ A2 Physics

Calm down.

I agree to be honest. I think most of A Level Physics is textbook answers. Having said that, the way the questions are phrased sometimes makes the exam tricky.

did I read section A's 6 marker correctly?

didn't it give you a choice of whether to describe an experiment based on varying distance between the counter and the source, or the experiment of putting different stuff in between the source and the counter? (you only had to describe one of these methods, right?)

I chose the first one, I described varying the counter distance. But the thing thay threw me off was that it suggested that the source was producing more than one type of radiation, and that you had to find it which ones it was?

I just wrote about plotting a graph of count rate and distance from source, and looking at the shape of the graph to tell which radiation were produced. This is how its done, right?

Yeah, I was debating this with myself at the time but in the book that's what it says for identifying each source of radiation

I chose the first experiment, and I basically said measure the count-rate with the source present at different measured distance, d from the source and the count-rate without the source present, record in a results table. If its Alpha then count-rate falls sharply with increased distance, if its Beta then count-rate falls gradually, and for gamma I talked about how you would verify the inverse square law relationship and if you plot a graph of corrected count-rate against d you get a straight line with negative intercept (= do the distance inside the sealed container).

I'm actually not entirely sure. I got 35 on the written paper. I believe the teacher gave me full marks for the practical procedure, but I can't remember what that's out of. I just remember looking it up before and it worked out to about 48 UMS on average.

Do you need the A* for Uni?

I presumed you had to choose one because it said or.... so i talked about the absorber experiment and the shortcomings, but the general experiment too and the principles behind it as well as describing it and talking about the safety precautions...


In terms of the paper itself, i found the written questions much easier. I normally depend on the maths but i made so many errors. The Astro 6 marker was beaut; there were so many points you could make about CCDs structure function advantages etc. I did say i'd use the lens as an objective (stupidly) lol. Apart from that, loved astro (except my wrong H value on the last question) especially the sneaky diffraction pattern graph for the Rayleigh Criterion

I needed 98/120 ish for an A* but given the sheer number of calculation errors i made (and missing out the last part of the pressure question) and the high grade boundaries for astro, i dont think itll happen :/ how did astro people find the paper?

I presumed you had to choose one because it said or.... so i talked about the absorber experiment and the shortcomings, but the general experiment too and the principles behind it as well as describing it and talking about the safety precautions...


In terms of the paper itself, i found the written questions much easier. I normally depend on the maths but i made so many errors. The Astro 6 marker was beaut; there were so many points you could make about CCDs structure function advantages etc. I did say i'd use the lens as an objective (stupidly) lol. Apart from that, loved astro (except my wrong H value on the last question) especially the sneaky diffraction pattern graph for the Rayleigh Criterion

I needed 98/120 ish for an A* but given the sheer number of calculation errors i made (and missing out the last part of the pressure question) and the high grade boundaries for astro, i dont think itll happen :/ how did astro people find the paper?

I think 9 maybe? Not too sure either...
Well I have an offer of A*AAa but the A* can be in either Maths or Physics so not necessarily, yourself?

did you not notice that the question asks for the experiment to find what radiation was emitted?

it even mentioned that it was suspected that the source was emitting both alpha and gamma radiation (unless I remembered wrong?)

this was what gave me a real headache, because the source was not definitely only emitting one type of radiation, so its not a simple case of just measuring the count rate, plotting it up and then seeing a pattern showing either one of the three types of radiation

the count rate you got, could've been the combined effect of more than one type of radiation

for the 6 marker would all marks be lost if i mentioned both techniques

Mine's similar - I need A*AAA and A* is not specified. But want as many A*s as I can bag

for the 6 marker would all marks be lost if i mentioned both techniques

wish I was in the same situation as you

I more or less tanked my practical units, which effectively means that I need full UMS in both unit 4 and 5 to have a chance of an A*, and this is assuming that I've scraped half of the UMS in the unit 6 practical

Same here! What course is your offer for?

Generally found Astro okay, the 6 mark CCD question was an absolute god send!
Pretty much all fine except putting that the lens would be objective (don't worry you're not alone) because I didn't have a clue

Natural Sciences (Physical), how about you?

Chemical Engineering

Omg dude this is assuming my ISA mark doesnt go down. I know it sounds silly but after putting in the effort for the past few units, messing up this unit makes me feel like all of it was a wasted effort. There is no way i got more than 60/75 on this paper (even that is a stretch) and astro is normally 58 ish for an A

How was Unit 4? I hope it was ok.... did you do the EMPA or the ISA?