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

Difficult to understand a wave.

  1. Jun 12, 2005 #1
    A wave is characterized by its wavelength or say frequency.

    say two identical monochromatic sources (torch1 and 2) are lit.

    what happens if the first torch 1 is lit for 5 seconds and the 2 is lit for 10 seconds starting at the same instant. (considering they emit a single wave only).

    if the torch 2 produces wave for twice the length of the 1st then are their energies different??

    if so then E=hv says that both should have the same energy??
    how come??
    pls explain!!

  2. jcsd
  3. Jun 12, 2005 #2
    If you are emitting light for 5 seconds, you are emitting a lot more than one photon. The energy of a photon is directly proportional to its frequency. If the light sources emit identical photons, then the energy of each photon will be identical.
  4. Jun 12, 2005 #3
    well thanks for replying..
    then what is the time period for emitting one photon?
  5. Jun 12, 2005 #4
    This is an impossible question. A photon either exists, or it doesn't. A lamp emits billions of them per second, but it doesn't take a definite 'time' to emit one.
  6. Jun 12, 2005 #5
    The total energy emitted by lamp 2 is twice as much as that emitted by lamp 1, but it is not due to the frequency of the photons, rather due to the luminoscity of the lamp.
  7. Jun 12, 2005 #6
    it means that the way i am viewing the wave as a long continuous one is totally wrong?? i guess so, is there a good place to better understand quantization?

    that would be really helpful
  8. Jun 12, 2005 #7
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook