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  1. J

    Studying Quantum Information and Computing

    Thanks, Just checked, its available from the university library, I will pick it up and start ready. Will this be accessible to me? or will I need further QM exposure?
  2. J

    Studying Quantum Information and Computing

    I have just finished my 2nd year of undergraduate study, which had the first pass of QM in it. I want to do a PhD in Quantum information/computing. What can I learn in my own time to get me closer to understanding QM information/computing? Currently I only know what we covered in lectures, and...
  3. J

    Coefficients of a particle in Linear superposition (QM)

    Wow, I was being an absolute idiot, and inputting A back in incorrectly, for some reason i was just putting the value of A back into <E_0|\phi> and <E_1|\phi> expecting to get one. Thankyou lol
  4. J

    Coefficients of a particle in Linear superposition (QM)

    1. Homework Statement a particle is in a linear superposition of two states with energy E_0 \ and\ E_1 |\phi> = A|E_0> + \frac{A}{(3-\epsilon)^{1/2}}|E_1> where: A \ > \ 0, \ 0\ <\ \epsilon \ <\ 3 What is the value of A expressed as a function of epsilon 2. Homework Equations P(E_0) \...
  5. J

    Electrons Absorbing Photons - Extra Energy

    objects are certain colours due to the fact that they REFLECT that colour of light. such that there phonons are opaque to that frequency. a photon is absorbed by an atom causing it to be excited and an electron moves to a higher energy state. photons will only be absorbed by atoms if they have...
  6. J

    A Newton Question

    yes W is always the hypotenuse, so if u want to use the angle alpha then yeah Wx would be W cos alpha. this is exactly the same as W sin theta. always resolve the triangle like this. when its in the form shown in the book its harder to visualise as it makes it seem that Wx is the hypotenuse...
  7. J

    A Newton Question

    W is always the hypotenuse due to it being the greatest value. imagine completing the vector triangle between W and Wx. the value at W would be theta from the original triangle
  8. J

    Acceleration confusion

    you are trying to use constant velocity equation v=s/t instead of a constant acceleration equation here are the variables s=displacement, t=time, u=initial velocity v=final velocity a=acceleration here are the constant acceleration equations s=ut+0.5at^2 v=u+at s=(v+u/2)*t v^2=u^2+2as...
  9. J

    Are quantum mechanical effects faster than speed of light?

    Maui, Let me show you with calculation as you are completely refusing to even think about what everyone is saying. the radius of the moon = 1737km if we assume the moon is a flat disc the diameter is 1737x10^3*2 = 3.474x10^6 divide the number by a millisecond (1x10^-3) we get 3.474x10^9...
  10. J

    Cosmology mysteries

    does the deep field image not show a galaxy of 13.2 billion light years away? this must mean stars formed before 10 billion years ago
  11. J

    Fermi energy approximation for white dwarfs

    where is the heat being produced in a white dwarf? I was under the assumption fusion had stopped.
  12. J

    Fermi energy approximation for white dwarfs

    I believe it is due to the degeneracy pressure not allowing electrons movement. I just had a thought would the white dwarf act as a solid as such where it has energy bands instead of energy levels? is this why it glows white?
  13. J

    Wave theory of light

    If you are refering to quantum theory then yes light is photons, but these are discrete energy packets and not a particle like a proton.
  14. J

    Wave theory of light

    there are no particles, light is an electromagnetic wave, a wave consisting of an electric field and a magnetic field sloshing back and forth so to speak. if you are talking about "particles" being photons, photons have particle type characteristics and are discrete packets of energy not...
  15. J

    How to uniformly charge an insulating sphere?

    is it not possible to uniformly heat the "insulating sphere" as to release conduction electrons?
  16. J

    Is potential energy real or fictious?

    Isn't GR based on the thought experiment of a light clock? I'm pretty sure the effects of GR are "real".
  17. J

    Destructive Interference of gamma waves

    Light is EM radiation, Gamma is EM radiation of high energy. If you were to induce interference with a single photon i.e. youngs slit experiment you will have constructive and destructive interference and a situations such as dale explained. Displacement is additive when talking about...
  18. J

    Electron changing energy state

    So when thinking about the photoelectric effect we have to consider the properties of the material rather than a single atom that makes sense. I am not advanced enough for the Shrodinger equation i'm afraid. but I get what your saying I think. lol Thanks for the clarification Popper I was...
  19. J

    Electron changing energy state

    When a photon is absorbed by an electron the electron moves from ground state to a higher energy lets say n=3. this electron can then drop back down and emit a photon of the exact energy as the photon that was absorbed. My question is why is there no work function or energy transfer as it...
  20. J

    Sun Diffraction

    If you use a white light bulb you should get a diffraction pattern where the central minima is white as the path difference is the same for each wave. The other maxima will be of different colours due to different path lengths and white light being made up of different wavelengths of light. I...
  21. J

    Diffraction grating of laser light

    technician, after seeing your reply I have noticed my calculator is still in radians from my math revision. now i get 5.29 down to 5. Thanks lol
  22. J

    Diffraction grating of laser light

    you are correct that should have been meter per line. I knew I must have been forgetting something. Thankyou
  23. J

    Diffraction grating of laser light

    1. Homework Statement a narrow beam of laser light (i.e coherent monochromatic light) wavelength 630nm is incident on a grating having 300 lines per mm. a piece of paper is curved 180 degrees beyond the grating. calculate how many spots of red light should be seen 2. Homework Equations...
  24. J

    Potential difference in parallel circuit

    http://physicsnet.co.uk/a-level-physics-as-a2/current-electricity/circuits/ - right at the bottom basically if you have a 12v supply with 3 components how can the PD across each component be 12 when 3x12 = 36v?
  25. J

    Potential difference in parallel circuit

    1. Homework Statement I am currently revising some AS level Circuit modules and i'm having trouble seeing how the P.D across 3 components in a parallel circuit can each have the same value as the P.D of the battery. I am probably just being dumb but its just not making sense! such as this...
  26. J

    Destructive Interference and coherent light in anti-phase

    thanks jtbell and sophie the explanations are very clear and make perfect sense. Is it known how this energy transfers from one wave to another?
  27. J

    Destructive Interference and coherent light in anti-phase

    Thank you very much Dale, I feel I have a greater understanding now. :smile:
  28. J

    Destructive Interference and coherent light in anti-phase

    Say a wave was sent through a waveguide one of length being an integer of the wavelength and the other being a non integer value, this produces destructive interference and a wave with a lower amplitude giving less intensity and energy, in this scenario there are no other waves present where has...
  29. J

    Destructive Interference and coherent light in anti-phase

    Thanks Sophie, I was actually thinking about the double slit experiment. Could you possible expand on this point:
  30. J

    Destructive Interference and coherent light in anti-phase

    I have a question about coherent light in anti-phase, I'm probably thinking about this wrong but I just cant understand what happens to the energy in the wave when two waves of the same wavelength, frequency and amplitude are in anti-phase as the resultant wave is 0.
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