physics

posted by .

A 75 W light source consumes 75 W of electric power. Typically only about 5% of this energy is emitted as visible light of wavelength 600 nm. (a) Calculate the frequency of the emitted visible light. (b) How many photons per second of visible light does the source emit? (c) Is the frequency of light the same thing as as the number of photons emitted per second?

  • physics -

    (a) frequency = c/(wavelength)
    (b) 75 W/(h*f)
    where f it the frequency and h is Plank's constant.
    (c) certainly not. Frequency does not depend upon brightness. Photons per second does.

  • physics -

    By the way, your "posted by" name is an incorrect statement, which disagrees with the facts and the question itself. What is that all about?

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. science

    In the process called fluorescence, some substances absorb photons of one kind of radiation (e.g) ultraviolet radiation), and give out photons of a different kind (e.g visible light). When infrared radiation falls on these materials, …
  2. Quantum Physics

    How is it a substance can emit photons of visible light after absorbing ultra violet photons but not with infrared radiation The re-emitted photons must be of lessor energy (longer wavelength) than the incident photons. In a one-photon …
  3. Physics

    We can reasonaly model a 75 W incandescent lightbulb as a sphere 6 cm in diameter. Typically, only about 5% of the energy goes to visible light; the rest goes largely to nonvisible infrared radiation. (a) What is the visible light …
  4. Physics

    A 75 W light source consumes 75 W of electric power. Typically only about 5% of this energy is emitted as visible light of wavelength 600 nm. (a) Calculate the frequency of the emitted visible light. (b) How many photons per second …
  5. Physics

    We can reasonably model a 75 W incandescent light bulb as a sphere 6.0 cm in diameter. Typically, only about 5% of the energy goes to visible light; the rest goes largely to non-visible light infrared radiation. (a) What is the visible …
  6. chemistry

    Find velocity of electron emitted by metal whose threshold frequency is 2.1*10^14 and when exposed to visible light wavelength of 5.09*10^-7
  7. Chemistry (Electrons in Atoms)

    The wavelength of visible light varies from 0.40 μm to 0.70 μm as the color of the light changes from violet to red. Calculate the energy of a photon whose wavelength is 0.67 μm HINT: From the wavelength and the speed …
  8. college chemistry

    Assuming that 9.0\% of the energy output of a 65W lightbulb is visible light and that the average wavelength of the light is 550 {\rm nm}, how many photons are emitted by the lightbulb each second?
  9. Chemistry

    E=hv E=energy h= Planck's constant =6.626 x 10^-34 v= frequency 1. What is the energy of light having a frequency of 2.28 x 10^12?
  10. Science

    1.Infrared radiation has wavelengths ranging from about 800 nm to 1 mm. What is the frequency of radiation of wavelength 970 nm?

More Similar Questions