Photon energy and calculating frequency

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SUMMARY

The discussion centers on calculating the frequency of a photon with an energy of 2.12 eV. The correct conversion of energy from electronvolts to joules is confirmed as 3.392 x 10-19 J using the conversion factor of 1 eV = 1.60 x 10-19 J. The frequency is calculated using the equation E = hv, leading to a frequency of 5.12 x 1014 Hz. The participants clarify that this frequency is reasonable when compared to the visible spectrum, and emphasize the importance of understanding the context of the results.

PREREQUISITES
  • Understanding of photon energy and its units (eV and Joules)
  • Familiarity with Planck's constant (h = 6.63 x 10-34 J·s)
  • Knowledge of the equation E = hv for calculating frequency
  • Basic concepts of the electromagnetic spectrum
NEXT STEPS
  • Learn about the relationship between energy, frequency, and wavelength in electromagnetic waves
  • Study the properties of the visible spectrum and its significance in physics
  • Explore the conversion between electronvolts and joules in detail
  • Investigate the implications of photon energy in various applications, such as photovoltaics
USEFUL FOR

Students studying physics, particularly those focusing on quantum mechanics and the properties of light, as well as educators looking for practical examples of photon energy calculations.

MathiasArendru
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Hello guys, I am having a bit of trouble with some homework

So I am told that a photon in a light beam has an energy og 2,12 eV. First i have to calculate the energy of it in joules, and since 1 eV is 1,60*10^-19 Joules 2,12 eV in joules is just 2,12*1,60*10^-19 = 3.392*10−19 J i got that.
Then i have to calculate the frequency of the light beam. I use the equation E = hv and just isolate v to get v = e/h. When i then plug in the numbers i get v = 3.392*10−19/6.63*10^-34(plancks constant) = 5.12*10^14 seconds. But isn't that a huuuge frequency? Anything I've done worng?

Thanks in advance!
 
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You shouldn't need to convert to joules. You should have a value for Planck's constant that is eV•s.

Also, if you're unsure what a reasonable frequency is, convert it to wavelength, and then see where that wavelength falls on the spectrum and compare that to the question. In this case if you convert to wavelength you'll find that this pretty much in the middle of the visible spectrum.
 
Last edited:
Actually you're right haha, when i first heard it, it just seemed like too much and i didnt think about it any further but obviously it is. and converting to joules was a task included in the assignment.
Thanks
 

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