QUANTUM PHYSICS SEMI-DESPERATE HELP

[suprarx7nut]

So I need an equation for some quantum physics shit. Anyone have a clue about any quantum mechanics shit?

This is the question...



A digital camera basically has an array of tiny light detectors (2000x1500 = 3MegaPixels = 3 million very tiny detectors covering a cm2 or so). In each of these detectors, photons that hit the detector excite electrons and these excited electrons are counted.

In a typical picture, the detector array in the camera is exposed to about 4.5x10-6 Watts of light for 10 ms. If you take 535 nm as an average wavelength for the light, what is the average number of photons that hit each pixel in a typical picture?

(4 SigFigs, make sure to input answer in the format 1.234E5)




COME ON GUYS, IMPRESS ME!!!!!

 

[Disced]

Good luck... I tried to ask come pre-calc stuff last quarter and none of these guys could help...

I'm not in physics until next quarter..!

 

[suprarx7nut]

^^Haha, ya i figured no one could help. I'm in third semester physics. It came after three semesters of calc and one of Differential equations..... so if anyone can help i'd be very surprised and impressed.

 

[swaq]

The member 'bluemyst' could help you... But she's pretty swamped with homework right now. (she is graduating in Physics this year) Oh yeah, and you said "come on guys, impress me".

 

[suprarx7nut]

^^When i say guys, i mean that in a uni-gender sense. "Guys" as a group of people, not necesarily males. Honestly I think girls are smarter anyway.


And way to go Bluemyst, physics is tough shit!

***Oh and i got an estimate of the answer. I found how many photons at 500nm make up a watt and just proprtioned that to the given wattage. My answer wont be exactly right, but its a close estimate, i think.

 

[aznwaterboy]

damn your one semester ahead of me lol. i'm taking electrostatics/circuits right now and the next semester will be thermodynamics and light stuff.

 

[americanjebus]

it makes sense to me but i dont know the order of operations your folowing nor the equations your using. havent covered that yet, sorry.

The people that are qualified to do this stopped coming to off topic.

 

[JustAnotherVictim]

Why don't you impress me with the answer.

 

[outofstep]

That's not quantum physics... In fact, that's a relatively simple intro physics question. No calculus is required for the answer. You can do it, it's just algebra.

 

[suprarx7nut]

^^The answer for those of you playing at home is.... well i cant remember what i got and they haven;t graded it yet, but I'll post it along with the math involved.

 

[suprarx7nut]

That's not quantum physics... In fact, that's a relatively simple intro physics question. No calculus is required for the answer. You can do it, it's just algebra.

Well the course is titled physics 2130, quantum mechanics in physics. And its the first couple weeks of class, so no, its not too advanced yet. but doesn't quantum physics just mean the science of light (i.e. light duality, wave/particle)?

And JAV, I'll post the answer when i get it back, i didn;t copy down what i got and i can't find the website i got the number from so i cant rework it. But i'll let everyone playing at home know.

 

[bluemyst]

And way to go Bluemyst, physics is tough shit!

***Oh and i got an estimate of the answer. I found how many photons at 500nm make up a watt and just proprtioned that to the given wattage. My answer wont be exactly right, but its a close estimate, i think.

Hehe, thanks. It sure seems tough right now - had a very hard midterm in complex optics this morning. Ugh.

I haven't done that stuff in a while but that sounds like a good approach. And outofstep is right - it's not really quantum, not yet. You want quantum, look up spin-1/2 systems and go through the complex notation and see what you think of it. And according to my prof, that is basic quantum. =P That example is only a two-state system... it gets nasty when you're at three or more. Er, nastier.

Oh, here we go: http://en.wikipedia.org/wiki/Two-state_quantum_system Wikipedia to the rescue! =)

 

[suprarx7nut]

Hehe, thanks. It sure seems tough right now - had a very hard midterm in complex optics this morning. Ugh.

I haven't done that stuff in a while but that sounds like a good approach. And outofstep is right - it's not really quantum, not yet. You want quantum, look up spin-1/2 systems and go through the complex notation and see what you think of it. And according to my prof, that is basic quantum. =P That example is only a two-state system... it gets nasty when you're at three or more. Er, nastier.

Oh, here we go: http://en.wikipedia.org/wiki/Two-state_quantum_system Wikipedia to the rescue! =)

Good luck on that midterm.

4.041 × 10^4 is the answer, but i wasn't even close. I had 1.3*10^8 Dammit. Looks like i gotta hit the books pretty hard before my test on Tues.

 

[bluemyst]

Yikes. Lots of studying is always a good idea. And I can't recommend anything better than actually doing a bunch of problems, but I'm sure you knew that already. =) Good luck!

 

[suprarx7nut]

thanks man, I'll be doin a lot of examples in the next few days.