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PHYA1 - Physics Unit 1 Exam - 24th May 2011

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Reply 40
Original post by robthefool
Can anyone help me with the prefixes like micro, kilo e.t.c and which are which? I always forget them! also a few examples iof you don't mind :smile: Thanks!


x10^9 = Giga e.g. GHz
x10^6 = Mega e.g. MHz
x10^3 = Kilo e.g. kHz
x10^-3 = Milli e.g. mHz
x10^-6 = Micro e.g. ?Hz
x10^-9 = Nano e.g. nHz

I gave the examples because it has to be in the right case ( lower or upper case)! If not you will lose marks!
Original post by Aarynn
x10^9 = Giga e.g. GHz
x10^6 = Mega e.g. MHz
x10^3 = Kilo e.g. kHz
x10^-3 = Milli e.g. mHz
x10^-6 = Micro e.g. ?Hz
x10^-9 = Nano e.g. nHz

I gave the examples because it has to be in the right case ( lower or upper case)! If not you will lose marks!


Thank you very much!!! :smile:
Reply 42
Original post by robthefool
Thank you very much!!! :smile:


That question mark is meant to be the symbol for mu, which is the lower case on this page :smile: http://en.wikipedia.org/wiki/Mu_(letter)
Original post by robthefool
Can anyone help me with the prefixes like micro, kilo e.t.c and which are which? I always forget them! also a few examples iof you don't mind :smile: Thanks!



x10^9 giga G
x10^6 mega M
x10^3 kilo k
x10^1 (normal, e.g. metres)
x10^-3 milli m
x10^ -6 micro µ
x10^-9 nano n
x10^-12 pico p
x10^-15 femto f

for the smaller values, milli is easy to remember as millimetres are so commonly used, nano sounds like nine (x10^-9) femto starts with f, as does fifteen (x10^-15), pico is rarely used and as it's so obscure I usually remember it haha, and micro is just... the other one that's not milli, nano, pico or femto! i'm sure there are mnemonics you could think up if you really get stuck remembering them :smile:

edit: sorry I was very slow posting this and was beaten to it, hope it's slightly helpful anyway!
Original post by robthefool
Can anyone help me with the prefixes like micro, kilo e.t.c and which are which? I always forget them! also a few examples iof you don't mind :smile: Thanks!


Pico = x 10 ^-12

Nano = x 10 ^-9

Micro = x 10 ^-6

Milli = x 10^-3

Kilo = x 10^3

Mega = x 10^6

Giga = x 10^9

Terra = x 10^12

Cool?
Thanks guys :smile: Also, I really don't understand neutrinos :\ just everything about them haha.. quantum physics really makes no sense for me haha..
(edited 12 years ago)
Original post by robthefool
Thanks guys :smile: Also, I really don't understand neutrinos :\ just everything about them haha.. quantum physics really makes no sense for me haha..


In Beta-minus decay, an antineutrino is released, carrying away some energy and momentum. Likewise, in beta-plus decay, a neutrino is emitted.
In terms of Leptons, which don't feel the strong nuclear force, there are two other types other than electrons - muons and taus, which are just heavy electrons really, and they each come with their own neutrino.
Neutrinos = zero mass, zero electric charge, only take part in weak interations, and can effectively pass through the earth without anything happening to them.

Oh and! With lepton numbers, there are three types according to electrons/muons/taus, so the particle and its respective neutrino each have a lepton number of that type of +1... if that makes sense? Like, an electron and an electron-neutrino both have an electron lepton number of +1, but a muon and tau lepton number of 0.

Lepton number conservation has to be separate, so you can't trade types of lepton numbers and consider them balanced.


Not sure if that was clear, just ask for more!
Original post by racheltaylor23
In Beta-minus decay, an antineutrino is released, carrying away some energy and momentum. Likewise, in beta-plus decay, a neutrino is emitted.
In terms of Leptons, which don't feel the strong nuclear force, there are two other types other than electrons - muons and taus, which are just heavy electrons really, and they each come with their own neutrino.
Neutrinos = zero mass, zero electric charge, only take part in weak interations, and can effectively pass through the earth without anything happening to them.

Oh and! With lepton numbers, there are three types according to electrons/muons/taus, so the particle and its respective neutrino each have a lepton number of that type of +1... if that makes sense? Like, an electron and an electron-neutrino both have an electron lepton number of +1, but a muon and tau lepton number of 0.

Lepton number conservation has to be separate, so you can't trade types of lepton numbers and consider them balanced.


Not sure if that was clear, just ask for more!



Thank you very much that was very clear :smile:
Reply 48
the 6 mark question? i have a feeling it may be on energy levels and photon emmision, anyone else got different opinions?
They do seem to love photoelectricity. I'm just going to go through the past papers and note what topics came up, see if any predictions can be made! Not that I'm going to rely on predictions, that could go veeery badly...
Reply 50
its either gonna be an explain the electricity experiment or something i photoelectrity i think:smile:
Original post by racheltaylor23
They do seem to love photoelectricity. I'm just going to go through the past papers and note what topics came up, see if any predictions can be made! Not that I'm going to rely on predictions, that could go veeery badly...


If you do have that magic tingly feeling and DO believe that you have a correct prediciton. Do please share it (:

Thanks in advance for securing my A grade x

PS. Dont tell these other f*ckers.
(edited 12 years ago)
To be honest, so far it just seems like every topic comes up in every paper :P
Reply 53
i would prefer it if the 6 marker was on photoelectricity. however im pretty sure they already asked one of that in jan 2011. so if that comes up i'd say its probably gonna be for one of those 3 or 4 marker ones. maybe two 3 markers or something, hopefully. but its most probably gonna be creating a circuit to work out resistance or to work out resistivity. something like that. gd luck everyone :smile:
on the jan 2011 paper question 6 (d) (i) and (ii) should'nt it be the otherway around. i though the current is the same in series and split in parrallel... :confused:
(edited 12 years ago)
Original post by bubblebuddy
Has anyone done the specimen paper?

For question 5, where you have to explain why the semiconductor diode protects the ammeter, I really don't understand why the answer is what it says in the mark scheme.

Can anyone help?


I don't really understand it either. It was a dodgy question I haven't come across before. Hopefully nothing like that will come up in the actual paper. Remember the specimen papers are a little different to the actual exam ones.
Reply 56
I keep thinking i'm going to get asked how an oscilloscope works XD So i've learnt that, i suggest you guys do too!
Original post by Aarynn
I keep thinking i'm going to get asked how an oscilloscope works XD So i've learnt that, i suggest you guys do too!


What would the answer be to that question exactly? :/
Reply 58
Original post by bubblebuddy
What would the answer be to that question exactly? :/


Ummm, i know it's in the actual AQA book, last thing in the whole unit. Something like;

Electrons are fired from an electron gun at the end of a glass tube in an oscilloscope, this forms a beam of electrons that are fired and hit the screen, producing light on the screen. The circuit being displayed in connected to this electron gun, or filament which emits electrons.

When a pd is applied across the X-plates in an oscilloscope the spot deflects horizontally, this is due to the X-plates being connected to the time-base circuit which makes the spot move left to right and then back again.

When a p.d. is applied across the Y-Plates the electrons are deflected depending on their energy from the electron gun (The voltage provided by your circuit). This causes the spot to move up and down. If the time-base is switched on the up and down motion combined with the left to right motion can form a wave form.

Okay, that's basically it as far as i can remember, you may not get asked that at all, but you should at least know what the inside of an oscilloscope looks like, and roughly how the x-plates and y-plates work. :biggrin:
Reply 59
Original post by jilebinator

Original post by jilebinator
on the jan 2011 paper question 6 (d) (i) and (ii) should'nt it be the otherway around. i though the current is the same in series and split in parrallel... :confused:


thats wat i thought at first but because you add a lamp (in series) , you increase its resistance and hence current decreases;
and in parallel : as pd accross the parallel lamps are the same, therefore current must be the same

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