1. K

    Why do photons change colour?

    If we shine white light on to a blue surface then only blue light is reflected and so we see the surface as blue. However, I am wondering about the bigger picture. I understand white is made up of multiple light frequencies, red, blue and green. These have different energies and we know E =...
  2. P

    The relation of colour charge to electric charge

    The relation of colour charge to electric charge Dirac has shown how the Klein-Gordon equation can be factored into two linear parts using 4x4 Dirac gamma matrices. [Dirac, P.A.M., The Principles of Quantum Mechanics, 4th edition (Oxford University Press) ISBN 0-19-852011-5] (E/c)^2 - P^2 -...
  3. O

    colour of sky

    why is sky blue? why not violet? Coz I know that shorter wavelength scattered more than longer wavelength. Violet is the shortest wavelength so why not violet?
  4. G

    Why do we see colours in bubbles?

    Colours can be seen moving around in a blown soap bubble. Explain how these are formed and why they move. I'm guessing it is something to do with the thickness of the bubble and light being somehow split but i'm not too sure other than that.
  5. S

    Colour addition/substraction problem (I think)

    Q: Sandra wore a red and white shirt to a party, at which all the lights were covered with blue filters. In this light, what colour did her shirt appear to be? A: Black and blue How can you tell?! Any help would be greatly appreciated! Thanks in advance!
  6. O

    In summer which colour cloth is appropriate?

    we know that only infrared is responsible for heat in sun light . Colour of infrared is not visible. Only white doesn't sense that it will reflect infrared or not. Then how can I say that white colour cloth is better in summer?
  7. P

    colour of the wet cloths seems deeper

    When the coloured cloths become wet it seems deeper coloured - Why?