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- Thread starter JayWalker
- Start date
nomz
Member
- Joined
- Feb 10, 2004
- Messages
- 173
JayWalker said:If anyone has any questions please post here and I will be happy to answer you, just getting a little bored here
wow how nice of you! thanks! I will remember that so when i actually start studying for physics i can get help on any problems i encounter- there's bound to be alot!
Jase
Member
blackbody - ultraviolet catastrophe and how it's solved by Plank's quanta.
-> classical physics dosn't work, introduce adhoc assumption of quanta.
mabye a couple of points on what a black body is, and the relationship between wavelength/frequency and intensity/temperature. thats about it.
superconductors - BSC theory -> cooper pairs, phonons, critical temperature.
Meissner effect-> eddy currents+ zero resistance = exclude field
Limitations of superconductors -> too cold, too brittle.
uses of supers -> Maglev, brakes, MRI scan (as the coil's core)
-> classical physics dosn't work, introduce adhoc assumption of quanta.
mabye a couple of points on what a black body is, and the relationship between wavelength/frequency and intensity/temperature. thats about it.
superconductors - BSC theory -> cooper pairs, phonons, critical temperature.
Meissner effect-> eddy currents+ zero resistance = exclude field
Limitations of superconductors -> too cold, too brittle.
uses of supers -> Maglev, brakes, MRI scan (as the coil's core)
Cepheids: Are an intrinsic variable. Their period of oscillation of their light curve is directly related to their luminosity. So by measuring their period you know their absolute magnitude so you can calculate there distance. They then can be used to calibrate distance measurements.Logix said:
Binary: You need to know the 4 types visual, eclipsing, spectroscopic and astrometric
Recognize the light curve of a eclipsing
The reason a binary is orbiting is the gravitational pull on each other. By measuring the period of orbit and radius of orbit you can calculate the mass of each star. This allows us to identify the masses of different types of stars.
Variable Star: Ant star that changes it brightness not due to the atmospheric twinkling.
Periodic: Change on a regular pattern. eg Cepheid or Eclipsing Binary
Non-periodic: Changes without a pattern. Eg Super novae or flares
Intrinsic: Caused by factors inside the star. Eg Supernovae Cepheids
Extrrinsic: Cause by external factors, Eg eclipsing binaries, rotation of a star.
If you are having problems have a look at the Emery site
http://webs.mn.catholic.edu.au/physics/emery/hsc_astrophysics.htm
OR hollows (he wrote a lot of the Astro syllabus)
http://outreach.atnf.csiro.au/education/senior/astrophysics/
Luminosity:Energy output from a star
Brightness: The energy output per square metre. So is the luminosity divided by the surface area
Magnitude is a measure of the brightness of a star but is not a linear scale but a log scale
Absolute magnitude: The magnitude when viewed from a standard distance of 10 parsec
Apparent magnitude: The magnitude of a star as viewed from Earth.
Brightness: The energy output per square metre. So is the luminosity divided by the surface area
Magnitude is a measure of the brightness of a star but is not a linear scale but a log scale
Absolute magnitude: The magnitude when viewed from a standard distance of 10 parsec
Apparent magnitude: The magnitude of a star as viewed from Earth.
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soha
a splendid one to behold
i have a question..can u explain reputations to me..how what are they for
if i have 13 what does that mean?
if i have 13 what does that mean?
Jase
Member
ahahah. Well everyone starts off with ten reputation points right. i think..or is that 13 points?
Well then, when you spam enough, people will start "giving"you rep points. It is allegory to the way a dog owner will give his/her dog dog biscuits after a neat trick. This will continue to happen until the dog eats enough biscuits and mutates into a super-canine thing with big sharp pointy teeth, which we will call "ego". See that little green bar under your name, that would be equivalent to "time spent on this forum" which is an inverse proxy indicator for "how little time I spend outdoors". So as the dog eats more and more, it gets bigger and bigger until it swallows its human owner and goes on a rampage throughout the city, mind you, the dog is now 100ft tall with big pointy teeth. Now, there reaches a certain point where the dog eats so much, it needs to relieve its bowels... this is what we call "becoming a moderator". There is another point where the Big Dog meets Godzilla and they have babies. But im not quite sure where that fits in yet.
So basically, if you are on 13, it means you are a skinny little Chihuahua yet to become the oversized rabid pitbull.
Well then, when you spam enough, people will start "giving"you rep points. It is allegory to the way a dog owner will give his/her dog dog biscuits after a neat trick. This will continue to happen until the dog eats enough biscuits and mutates into a super-canine thing with big sharp pointy teeth, which we will call "ego". See that little green bar under your name, that would be equivalent to "time spent on this forum" which is an inverse proxy indicator for "how little time I spend outdoors". So as the dog eats more and more, it gets bigger and bigger until it swallows its human owner and goes on a rampage throughout the city, mind you, the dog is now 100ft tall with big pointy teeth. Now, there reaches a certain point where the dog eats so much, it needs to relieve its bowels... this is what we call "becoming a moderator". There is another point where the Big Dog meets Godzilla and they have babies. But im not quite sure where that fits in yet.
So basically, if you are on 13, it means you are a skinny little Chihuahua yet to become the oversized rabid pitbull.
soha
a splendid one to behold
so i dont really need to worry about it
i thought i was getting bad reputations or something..
i thought i was getting bad reputations or something..
gordo
Resident Jew
your rep can only go up
unless mods change it or something
unless mods change it or something
wat is the deal with these rep thingys? i have no idea wat u's r talking about
another question: do we need to know anything bout flare stars and novas and stuff to do with variables? each textbook has a little info on them in terms of how they are irregular variables. but the syllabus doesnt seem to talk bout them at all so im confused as to whether we need to know anyting bout them
another question: do we need to know anything bout flare stars and novas and stuff to do with variables? each textbook has a little info on them in terms of how they are irregular variables. but the syllabus doesnt seem to talk bout them at all so im confused as to whether we need to know anyting bout them
*~Unique~*
New Member
Hello,
I am not sure if this is the place to post this question but i will anyway. If this is not the appropriate place, please tell me where to go.
Okay. I am doing a practical on DC circuits and am not quite certain about the relationship between temperature and resistance?...If there is an increase in the temperature, is there a decrease in the resistance? Because the particles are more mobile and have more energy, thus enabling them to transfer the charge/energy thingo across a resistor faster?
And another: Are the lamps in a motor car usually connected in series or parallel, and why?
I am not sure, but taking a stab in the dark, are they in parallel because if they were in series they would not be able to individually turn on and off as they do on the dashboard.
I will be back on tomorrow, hopefully you can help me.
Thankyou.
Kira
I am not sure if this is the place to post this question but i will anyway. If this is not the appropriate place, please tell me where to go.
Okay. I am doing a practical on DC circuits and am not quite certain about the relationship between temperature and resistance?...If there is an increase in the temperature, is there a decrease in the resistance? Because the particles are more mobile and have more energy, thus enabling them to transfer the charge/energy thingo across a resistor faster?
And another: Are the lamps in a motor car usually connected in series or parallel, and why?
I am not sure, but taking a stab in the dark, are they in parallel because if they were in series they would not be able to individually turn on and off as they do on the dashboard.
I will be back on tomorrow, hopefully you can help me.
Thankyou.
Kira