PHYA5 ~ 20th June 2013 ~ A2 Physics

Hello everyone
Did anyone learn the pauli exclusion principle to explain resistive forces on gravitational collapse of a star?

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.

Hey, does anyone know when calculating the mass defect, should the mass of the electrons be taken into consideration?

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?

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

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.

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

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.

Are you doing AQA physics?
Never heard of absorption tests or inversion tube?

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

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.

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!

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

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!

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