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emlee
09-21-2005, 01:49 PM
Why oh WHY did I take physics for A level...anyone?

first question of my FIRST physics homework...

Calculate the wavelength of a y-ray photon which has an energy of 1.6x10 to the power of -15 J.

Part 2 is the same but for an x-ray photon and comparing the differences of speed and their abilitys to penetrate a given material, another question is asking me to prove how Rutherford discovers the nuvlear radius of gold is much smaller than its atomic radius...

Oh and it all has to be done for tomorrow...

http://forums.ubi.com/images/smilies/35.gif

stonelance
09-21-2005, 02:13 PM
Hmm I think this is right,

Use Planck's Law: http://www.atis.org/tg2k/_planck_s_constant.html

Wavelength = speed of light/frequency

So you should be able to calculate it using this equation:
E = h*c/lambda
h = 6.626x10^-34 Joules*s
c = 3x10^8 m/s
E = energy of photon in Joules
lambda = wavelength in meters

Wavelength for x-rays and gamma rays are usually around 1x10^-9 m so if its less than an order of magnitude from that then you should be on the right track. I tried it and got 1.24*10^-10 m, hopefully you get the same thing.

For the second question x-rays and y-rays should both be the same speed since the speed of light is constant. The wavelengths will be different though.

As for the Rutherford part, google is your friend. Just search for "Rutherford experiment" or something like that. The basic idea is that if the nucleus of a gold atom was the same radius as the atom then all the particle that are fired through the gold foil should be deflected, as they will all collide with the atoms and bounce off. What actually happens is that most of the particles go straight through the foil showing that there is a lot of empty space between the nuclei of adjacent atoms.

I <3 physics, if you couldnt tell.

mastachief-118
09-21-2005, 02:31 PM
Physics and me not something you will ever find together.

Ninja Kn1ght
09-21-2005, 02:33 PM
I really loved Physics. Particle and nuclear physics was my favourite section.

Flyn_Tagart
09-21-2005, 05:09 PM

MagicMagician
09-21-2005, 05:45 PM
I toke this last year, got an A on it. Luckly tho my teacher was nice and gave all open book tests so....if you need anymore help with this stuff I will be more then happy to help http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif.

DocHolidazed
09-21-2005, 06:32 PM
Stone, that was an awesome display of internet aided calculation. very well done.

stonelance
09-21-2005, 06:40 PM

But seriously, I remembered the Rutherford experiment, 'cause that one is kinda cool. Who bothers to memorize physics equations anyways, especially when you havent used them in 5+ years.

mrbagelrocks
09-21-2005, 06:45 PM
... and here I thought the Internet was used only for massive spread of pornography and chat forums.

Physics is phun.

I read a book recently called The Elegant Universe which has some pretty cool ideas concerning the theory of everything. It seems a bit far-fetched, though. I've been through calculations myself that only compounded on themselves. It turned out that I was looking at the problem the wrong way and a slightly different approach resulted in the same "answer" but with a much simpler execution.

PrOjEcTxMaYhEm1
09-22-2005, 05:14 AM
Originally posted by emlee:
Why oh WHY did I take physics for A level...anyone?

first question of my FIRST physics homework...

Calculate the wavelength of a y-ray photon which has an energy of 1.6x10 to the power of -15 J.

Part 2 is the same but for an x-ray photon and comparing the differences of speed and their abilitys to penetrate a given material, another question is asking me to prove how Rutherford discovers the nuvlear radius of gold is much smaller than its atomic radius...

Oh and it all has to be done for tomorrow...

http://forums.ubi.com/images/smilies/35.gif

That is so easy Emlee. The answer is C. Its always C.

Captain JeB
09-22-2005, 09:56 AM
Originally posted by Flyn_Tagart:

I got 41.8. Did you round up?

PacNW_CE
09-22-2005, 11:51 AM
Originally posted by mrbagelrocks:
... and here I thought the Internet was used only for massive spread of pornography and chat forums.

Physics is phun.

I read a book recently called The Elegant Universe which has some pretty cool ideas concerning the theory of everything. It seems a bit far-fetched, though. I've been through calculations myself that only compounded on themselves. It turned out that I was looking at the problem the wrong way and a slightly different approach resulted in the same "answer" but with a much simpler execution.

I really liked The Elegant Universe Too. Somewhat related and equally entertaining is the book The curve of binding energy. Talks about nuclear fission Vs fusion, and some dude who was one of the pioneers of modern physics.

Interestingly enough, I hated physics in college. Chemistry was a lot easier for me. No matter how hard I studied, I always got a B+/A-.

emlee
09-22-2005, 12:44 PM
Originally posted by Captainjeb:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Flyn_Tagart:

I got 41.8. Did you round up? </div></BLOCKQUOTE>

okay... I got...

(6.63x10 ttpo-34) x (3.00x10 ttpo8)
which = 1.989x10 ttpo-23

1.989x10 ttpo-23 divided by 1.6x10 ttpo-15 = 0.000000012 OR 1.2 x10 ttpo-8

the equation is

wavelength= hc/e, c= the speed of light, e= the energy, and h= plancks constant.

Ninja Kn1ght
09-22-2005, 01:22 PM
I think the 42 thing is a HGGTG reference, not a real answer. lol

BitSeraph
09-22-2005, 01:36 PM
Originally posted by Captainjeb:
I got 41.8. Did you round up?
Hold me back... just hold me back...

PacNW_CE
09-22-2005, 02:31 PM
BTW Em, your prof is an ex Nazi. If you were first year applied physics majors at Stanford, I'd expect that assignment. Did they give you any lecture on how to solve this particular problem, or do they just assume you will know how to do it via osmosis?

I hate teachers who don't teach. Show me someone who sucks at math and I'll show you someone who had an awful teacher.

stonelance
09-22-2005, 02:32 PM
Originally posted by emlee:
(6.63x10 ttpo-34) x (3.00x10 ttpo8)
which = 1.989x10 ttpo-23

I think you did something wrong. That should equal 1.989x10 ttpo-25.

If you are still getting the same answer my guess is you might be using your calculator wrong. Make sure you are not typing in 6.63x10E-34 etc, because that will make all your numbers 10 times too big, since the E includes the "times 10 ttpo". If you did this it would make your calculation 100 times too big, which is what happened from the looks of things.

PacNW_CE
09-22-2005, 03:14 PM
am I totally screwing up my algebra or shouldn't

e=(h*lamda)/c

simplify to lamda = ec/h?

multiply the c on both sides gives you ec = h*lamda

devide h from both sides gives you ec/h = lamda

That being the case I get 7.24x10^26 M

arc14716
09-22-2005, 04:17 PM
42 is definitely a Hitchikers reference.

After reading all of the above comments, I'm so glad I didn't go beyond chemistry class in high school. It was bad enough memorizing all of those formulas, elements, and everything else. Then working in the lab and writing lab reports, explaining every thing that happened in your experiments.

Well, good luck with your physics class, emlee. I'm eagerly awaiting the sequal to this topic: GAAAHHHHHHHHHHHHHHHHH WTF NOW?!?!?!?!?!?!

stonelance
09-22-2005, 07:07 PM
Whops looks like I wrote the equation wrong in my post. Got the lambda and c mixed up. I was using the right equation just wrote it down wrong in my post. I've fixed it up now, hopefully that didnt cause any confusion heh.

09-22-2005, 08:12 PM
You oughta love Vector calculation when you get to it! Good Luck Emlee!

TheGoodEd
09-22-2005, 10:55 PM
If anyone ever needs help writing their thesis on "the 18-35 demographic and its relevance in propagating the 'new' Media", just give me a holler. Till that time comes, though, I'll leave the physics to you folks.

brookelyn_FD
09-23-2005, 07:18 AM
Why did I open this thread first. It's 7am and now my brain hurts.

DirtyDiva
09-23-2005, 07:38 AM
I opened it at 10am and I'm done for the day...Thanks guys... LOL

Voodoorocks
09-23-2005, 10:27 AM
i wont be takin physics if am gunna be be a forensic scientist its biology and chem for me plus it and photography

emlee
09-23-2005, 01:23 PM
Originally posted by arc14716:
42 is definitely a Hitchikers reference.

After reading all of the above comments, I'm so glad I didn't go beyond chemistry class in high school. It was bad enough memorizing all of those formulas, elements, and everything else. Then working in the lab and writing lab reports, explaining every thing that happened in your experiments.

Well, good luck with your physics class, emlee. I'm eagerly awaiting the sequal to this topic: GAAAHHHHHHHHHHHHHHHHH WTF NOW?!?!?!?!?!?!
Well, I was planning that for question 3 http://forums.ubi.com/images/smilies/16x16_smiley-sad.gif

but yes, I think I am using my calculater wrong... I tried to work through some of the answers today (yes, work STILL not handed in) with a mate, when I seem to have one or two extra digits after my answers.
http://forums.ubi.com/groupee_common/emoticons/icon_frown.gif

Area_52
09-24-2005, 12:02 AM
Originally posted by emlee:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by arc14716:
42 is definitely a Hitchikers reference.

After reading all of the above comments, I'm so glad I didn't go beyond chemistry class in high school. It was bad enough memorizing all of those formulas, elements, and everything else. Then working in the lab and writing lab reports, explaining every thing that happened in your experiments.

Well, good luck with your physics class, emlee. I'm eagerly awaiting the sequal to this topic: GAAAHHHHHHHHHHHHHHHHH WTF NOW?!?!?!?!?!?!
Well, I was planning that for question 3 http://forums.ubi.com/images/smilies/16x16_smiley-sad.gif

but yes, I think I am using my calculater wrong... I tried to work through some of the answers today (yes, work STILL not handed in) with a mate, when I seem to have one or two extra digits after my answers.
http://forums.ubi.com/groupee_common/emoticons/icon_frown.gif </div></BLOCKQUOTE>hey Emlee i would help ya but my head hurts il help ya when i can and also mabye you should just like ask your dad or moms thoe

PacNW_CE
09-26-2005, 10:08 AM
Originally posted by stonelance:
Whops looks like I wrote the equation wrong in my post. Got the lambda and c mixed up. I was using the right equation just wrote it down wrong in my post. I've fixed it up now, hopefully that didnt cause any confusion heh.

Nope. Didn't screw me up at all. http://forums.ubi.com/images/smilies/351.gif

Physics is applied mathmatics, and in this instance applied algebra. Wait until they start to mix in calculus. That's when you start losing your hair and question your own intelegence.

Firefly0117
09-29-2005, 01:38 PM
Good luck with that stuff....
Im still trying to forget that stupid 'grammar' **** they keep attempting to teach me.