Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Have a pretty basic chem problem about lights and radiation

  1. Oct 1, 2008 #1
    An instrument can detect 9450 photons of light of wavelength of 8.065 × 10^-8 m. What is the minimum amount of energy in J to which the instrument is sensitive? Express answer in scientific notation..

    i have tried to use the e = (planck's constant) ( speed of light ) / (wavelenghth) but i am not sure how the photons figure is used
     
  2. jcsd
  3. Oct 1, 2008 #2

    Borek

    User Avatar

    Staff: Mentor

    If one photon carries 10-18 J of energy, how much energy is carried by two identical photons?
     
  4. Oct 1, 2008 #3
    where did you get 10^-18
     
  5. Oct 1, 2008 #4

    Borek

    User Avatar

    Staff: Mentor

    Nowhere, it is not directly related to the question. I could as well ask "If one photon carries 1018 J of energy, how much energy is carried by two identical photons?", although that'll be quite a photon :bugeye:
     
  6. Oct 1, 2008 #5
    so how would i know how much energy does each photon carry
     
  7. Oct 1, 2008 #6

    Borek

    User Avatar

    Staff: Mentor

    You have already listed equation that allows calculation of the energy of a single photon.
     
  8. Oct 1, 2008 #7
    so would i plug the wavelength into the equation and multiply by the number of photons and get my answer?
     
  9. Oct 1, 2008 #8

    Borek

    User Avatar

    Staff: Mentor

    Exactly.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook