# PHYA5 ~ 20th June 2013 ~ A2 PhysicsWatch

Announcements
6 years ago
#1081
(Original post by TheMJCG)
Hello everyone
Did anyone learn the pauli exclusion principle to explain resistive forces on gravitational collapse of a star?
I think you're going into degree level physics here... but yeah, electron degeneracy pressure would be used in Pauli's exclusion principle.
0
6 years ago
#1082
(Original post by Thr33)
Likewise :P

Here's the list:
Rutherford Experiment/X-Ray Diffraction; Calculating the Radius of the Nucleus - Unlikely, came up in 2012. Need to know it though, just in case.
Ionisation Chamber Experiment - See below.
Cloud Chamber - How does it differentiate between radiation types? - I don't really see this coming up though - not actually that much to talk about.
Absorption tests -
Geiger Tube - Same as Ionisation/Cloud chamber. Then again, they could do something about calculating count rate - removing background rate etc.
Nuclear Reactors - Came up a few years ago, but they could relate it to fission vs. fusion in general.
Inversion Tube/Heating Element - Calculating Heat Capacity; As far as I know, this hasn't come up - so may be worth looking over. It's fairly like the sort of questions you get for PSAs.
X-Ray diffraction? Do you mean electron diffraction?
0
6 years ago
#1083
(Original post by Emzy94)
Hey, does anyone know when calculating the mass defect, should the mass of the electrons be taken into consideration?
I don't think so, due to the electron number in each of the atoms stay the same hence are a constant and cancel out when doing the calculations.
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6 years ago
#1084
(Original post by Thr33)
Likewise :P

Here's the list:
Rutherford Experiment/X-Ray Diffraction; Calculating the Radius of the Nucleus - Unlikely, came up in 2012. Need to know it though, just in case.
Ionisation Chamber Experiment - See below.
Cloud Chamber - How does it differentiate between radiation types? - I don't really see this coming up though - not actually that much to talk about.
Absorption tests -
Geiger Tube - Same as Ionisation/Cloud chamber. Then again, they could do something about calculating count rate - removing background rate etc.
Nuclear Reactors - Came up a few years ago, but they could relate it to fission vs. fusion in general.
Inversion Tube/Heating Element - Calculating Heat Capacity; As far as I know, this hasn't come up - so may be worth looking over. It's fairly like the sort of questions you get for PSAs.
What exactly are the Cloud Chamber/Ionisation Chamber experiments?
I'm sure I should have notes on them, but I can't find anything in my own notes or in the text book
0
6 years ago
#1085
(Original post by amish123)
X-Ray diffraction? Do you mean electron diffraction?
Yeah, course - wrote that out whilst doing the astro 6 marker on telescopes...woops!
Thanks!
0
6 years ago
#1086
Could someone show me how to do June 2012 Section A 3Bi please?
0
6 years ago
#1087
(Original post by HanaTurtle)
What exactly are the Cloud Chamber/Ionisation Chamber experiments?
I'm sure I should have notes on them, but I can't find anything in my own notes or in the text book
Page 152 in the AQA A2 Physics textbook.

If you don't have it, hit me up again and I'll type something out quickly.
0
6 years ago
#1088
Can someone explain how I can find "d" using the formula m-M=log(d/10) in Astrophysics..I forgot how to use log functions
0
6 years ago
#1089
(Original post by OmegaKaos)
Rutherford Experiment
Ionisation Chamber
Cloud Chamber
Absorption tests
Geiger Tube
Thermal Reactors
Both for finding specific heat capacity- inversion tube and circuit

Not to mention kinetic theory of gases may come up.
Are you doing AQA physics?
Never heard of absorption tests or inversion tube?
0
6 years ago
#1090
(Original post by Rorschace)
Can someone explain how I can find "d" using the formula m-M=log(d/10) in Astrophysics..I forgot how to use log functions
((m-M)/5) = log(d/10) (You're missing out a 5 in that formula)

So: 10 ^ ((m-M)/5) = d/10

-> 10 x 10 ^ ((m-M)/5) = d
2
6 years ago
#1091
(Original post by Thr33)
Page 152 in the AQA A2 Physics textbook.

If you don't have it, hit me up again and I'll type something out quickly.
I've only got the CGP text book, and that doesn't have anything in it, well that I can find, probably being stupid and missing it!

Could you quickly explain it? Thanks!
0
6 years ago
#1092
(Original post by AndyKirwan)
Are you doing AQA physics?
Never heard of absorption tests or inversion tube?
Absorption tests is really basic stuff about "blocking" radiation with a sheet of paper, concrete, lead etc. Highly doubt it would come up but it's listed as a core practical.

Inversion tube is relating gain in ke from gpe to a raise in temperature. Ball bearings in a tube - invert it - you know distance fallen and, if you have a thermometer in it, the raise in temperature. mgh = mc(delta(t)); solve for c.
0
6 years ago
#1093
(Original post by Rorschace)
Can someone explain how I can find "d" using the formula m-M=log(d/10) in Astrophysics..I forgot how to use log functions
I do
$\dpi{200} 10^{\left ( \frac{m-M}{5}+log10 \right )}$
1
6 years ago
#1094
(Original post by Thr33)
((m-M)/5) = log(d/10) (You're missing out a 5 in that formula)

So: 10 ^ ((m-M)/5) = d/10

-> 10 x 10 ^ ((m-M)/5) = d

Yup I realised I missed out the 5 only after posting it..But Thanks a lot though!
0
6 years ago
#1095
(Original post by Thr33)
Absorption tests is really basic stuff about "blocking" radiation with a sheet of paper, concrete, lead etc. Highly doubt it would come up but it's listed as a core practical.

Inversion tube is relating gain in ke from gpe to a raise in temperature. Ball bearings in a tube - invert it - you know distance fallen and, if you have a thermometer in it, the raise in temperature. mgh = mc(delta(t)); solve for c.
Right, thanks the absorption test makes sense, honestly never heard of that inversion tube before - cheers!
0
6 years ago
#1096
(Original post by HanaTurtle)
I've only got the CGP text book, and that doesn't have anything in it, well that I can find, probably being stupid and missing it!

Could you quickly explain it? Thanks!
Course I can :P

An Ionisation Chamber:

Chamber with air at 1 atm pressure, with a source outside the chamber. When radiation enters the chamber, it causes ionisation; and these ions are attracted to either one of the "electrodes" - either the wall of the chamber, or a central metal electrode placed within the chamber (these are connected in a circuit, with a basic cell, and a picoammeter in series). As such, the movement of ions means that there is a movement of electrons, so a current is generated (as seen on the ammeter). The current is proportional to the number of ions created per second. (So is higher for alpha than beta etc.)

A Cloud Chamber:

Supersaturated air at a very low chamber (eg with ethanol vapour). Ionisation in the air causes a track of condensed vapour - ionising particle causes the formation of droplets. Alpha particles produce straight tracks radiating from the source, all of the same length - because they are (relatively) heavy and all of the same energy.
Beta particles produce wispy tracks that are deflected by collisions with the air molecules. They're less ionising so they tracks are fainter, and they have varying lengths (as the ke of beta particles varies).

Enjoy!
1
6 years ago
#1097
(Original post by Thr33)
Course I can :P

An Ionisation Chamber:

Chamber with air at 1 atm pressure, with a source outside the chamber. When radiation enters the chamber, it causes ionisation; and these ions are attracted to either one of the "electrodes" - either the wall of the chamber, or a central metal electrode placed within the chamber (these are connected in a circuit, with a basic cell, and a picoammeter in series). As such, the movement of ions means that there is a movement of electrons, so a current is generated (as seen on the ammeter). The current is proportional to the number of ions created per second. (So is higher for alpha than beta etc.)

A Cloud Chamber:

Supersaturated air at a very low chamber (eg with ethanol vapour). Ionisation in the air causes a track of condensed vapour - ionising particle causes the formation of droplets. Alpha particles produce straight tracks radiating from the source, all of the same length - because they are (relatively) heavy and all of the same energy.
Beta particles produce wispy tracks that are deflected by collisions with the air molecules. They're less ionising so they tracks are fainter, and they have varying lengths (as the ke of beta particles varies).

Enjoy!
Thank you so much!
0
6 years ago
#1098
(Original post by HanaTurtle)
What exactly are the Cloud Chamber/Ionisation Chamber experiments?
I'm sure I should have notes on them, but I can't find anything in my own notes or in the text book
Don't quote me on this but those experiments that you've just mentioned are in the book to highlight the characteristics of the 3 types of radiation. I.e i don't think they'll ask a question where you have to explain the experiment etc. But of course they can ask you questions on the penetrative and ionising effects of the 3 radiations. Hope that is clear.
0
6 years ago
#1099
(Original post by Thr33)
Course I can :P

An Ionisation Chamber:

Chamber with air at 1 atm pressure, with a source outside the chamber. When radiation enters the chamber, it causes ionisation; and these ions are attracted to either one of the "electrodes" - either the wall of the chamber, or a central metal electrode placed within the chamber (these are connected in a circuit, with a basic cell, and a picoammeter in series). As such, the movement of ions means that there is a movement of electrons, so a current is generated (as seen on the ammeter). The current is proportional to the number of ions created per second. (So is higher for alpha than beta etc.)

A Cloud Chamber:

Supersaturated air at a very low chamber (eg with ethanol vapour). Ionisation in the air causes a track of condensed vapour - ionising particle causes the formation of droplets. Alpha particles produce straight tracks radiating from the source, all of the same length - because they are (relatively) heavy and all of the same energy.
Beta particles produce wispy tracks that are deflected by collisions with the air molecules. They're less ionising so they tracks are fainter, and they have varying lengths (as the ke of beta particles varies).

Enjoy!
I don't think this can come up (to the extent that you've described). See above but i'm pretty sure those experiments are in the book to help you gage the characteristics of the 3 types of radiation. They may, for example, tell you something about the experiment and then get you to compare the 3 types or something like that.
0
6 years ago
#1100
(Original post by Lepton)
Haha fair enough
We're like the opposite then! i only needed 30/150 UMS in Chemistry to get my B and I've definitely done more Physics revision that Chemistry!
No I did mine last wednesday - OCR
Well at least now you can relax and not have to revise frantically last minute like me!

Good luck for the exam
0
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