How Many Photons Does a 25W Monochromatic Light Bulb Emit Per Second?

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SUMMARY

A 25W monochromatic light bulb emitting light at a wavelength of 650nm emits approximately 3.84 x 10^20 photons per second. This calculation is derived using the formula W = hf, where W is the power in watts, h is Planck's constant (6.626 x 10^-34 J·s), and f is the frequency of the light. The frequency can be calculated using the speed of light divided by the wavelength, leading to the conclusion that the energy of a single photon is 3.1 x 10^-19 J.

PREREQUISITES
  • Understanding of Planck's constant (6.626 x 10^-34 J·s)
  • Knowledge of the speed of light (approximately 3 x 10^8 m/s)
  • Familiarity with the relationship between wavelength and frequency
  • Basic principles of energy calculations in physics
NEXT STEPS
  • Research the calculation of photon energy using the formula E = hf
  • Explore the relationship between wavelength and frequency in electromagnetic radiation
  • Learn about the implications of photon emission in various light sources
  • Investigate other applications of Planck's constant in quantum mechanics
USEFUL FOR

Physics students, educators, and anyone interested in the quantification of light and its properties, particularly in the context of monochromatic light sources.

soul5
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How many photons per second are emitted by a monochromatic light bulb (650nm) that emits 25 W of power?

W=hfo

hf=Ek + W

P=W/t


is there a way we can find power? how do I solve this question?
 
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Hint: What's the energy of a single 650nm photon? (This is not a photoelectric effect problem.)
 

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