Recent content by orange

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    Why Do Some Photons Get Reflected While Others Are Absorbed?

    So an ideal blackbody is a collection of atoms which together are able to absorb photons of all wavelengths since it is made of such a variety of elements? Photon-reflection in a crystal were used to examine x-rays in 1912 by W.L. Bragg. How do you mean reflection is done by a group of...
  2. O

    Why Do Some Photons Get Reflected While Others Are Absorbed?

    But an ideal blackbody absorbs radiation of all wavelengths. How is this compatible with the above statement?
  3. O

    Why Do Some Photons Get Reflected While Others Are Absorbed?

    How do an atom "know" when to absorb a photon, and when not to? It seems like an atom absorbs all photons that either has energy that corresponds to the difference between two energylevels, or has any type of energy at all in which case the photon energy helps speed up the atoms oscillations...
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    Solving Calculus Question: x^4 + y^4 = 17, x + 8y = 30

    Hey hey. I have this question I have a hard time figuring out. Here is the assignment as I got it: What points are the closests between the functions x^4 + y^4 = 17 and x + 8y = 30? I have started a few times but never really got far. I thought the line between the closets...
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    Last part of extreme value problem

    Hey hey! I'm trying to figure out the extreme values of f(x,y,z) = (x^2 + y^2 - z^2) * e^-(x^2+y^2+z^2) I do partial differentiation to find where all derivatives are zero, and after some work come to the equation 2(x^2 + y^2 - z^2) = 0 So one obvious extreme point is (0,0,0)...
  6. O

    What is the Integral of e^(-bx^2) Using Substitution?

    Thanks a lot George and StatusX. Appreciate you taking your time. :!)
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    What is the Integral of e^(-bx^2) Using Substitution?

    I'll take the whole problem: The integral (from zero to +infinity) of c*x^2*e^(-bx^2) dx = 1 I get the clue: integral (from zero to +infinity) of e^(-x^2) = sqrt(pi) / 2 What is c?
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    What is the Integral of e^(-bx^2) Using Substitution?

    But is sqrt(b) a constant when it is the same thing as y/x? Can I move it outside the integral?
  9. O

    What is the Integral of e^(-bx^2) Using Substitution?

    Hello! I've got a problem I've been working on for hours. I get a clue; If the integral (from zero to infinity) of e^(-x^2) is sqrt(pi)/2, what is the integral (from zero to infinity) of e^(-bx^2)? I've tried substitution, but I kind of got it wrong. If x = y/sqrt(b), I get the same...
  10. O

    Light's reflection - wats ur perception?

    Could you post the images or links to them? That would make it a lot easier to give a good answer.
  11. O

    Aerobic Microbes: Imre Friedmann Research on Mars

    Hello all skilled biologists reading this post. Researcher Imre Friedmann et al. have selected a couple of critters suited for Mars if man were to warm it up. Two of these are aerobic; Matteia and Deinococcus radiodurans. I was wondering if the oxygen pressure on Mars is high enough for...
  12. O

    Estimating Mass Inside Galaxy Using Centrifugal Force

    I have another exam question, which I'm having some slight problems with... "In a particular galaxy the velocity curve is constant over a large range of radii, and equal 300 km/sec at a particular radius of 10kpc in this range. Estimate the mass inside this radius." Can I use centrifugal...
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    Effective Potential Method for Solar System Orbits

    Thanks alot! And I mean a lot! :-)
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    Effective Potential Method for Solar System Orbits

    Hey everyone! I have an exam question, but I don't know how to approach it. The question is, "Discuss orbits of bodies in the Solar System using the effective potential method." I thought about every planet having a certain amount of kinetic and potential energy, showing how they...
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    What Is the Difference Between Flux and Intensity in Astronomy?

    Hey everyone! What is really the difference between flux and intensity in astronomy? What I understand they are two different words of the same thing, namely energy per square length unit per time unit. I appreciate any help, thanks alot!
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