Light Intensity and Wavelength

(Wien's law: )

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Barzin Badiee 2K
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Light Intensity and Wavelength

Postby Barzin Badiee 2K » Sat Oct 14, 2023 5:53 pm

From what I understand, light intensity is not dependent on frequency or wavelength, rather it is dependent on amplitude. According Wien's law, lambda max is inversely proportional to the absolute temperature. And according to the Stefan-Boltzmann law, the intensity is directly proportional to the fourth power absolute temperature. Based on all of this, if we relate the equations, wouldn't intensity be proportional to the fourth power of (1/lamba max) meaning that light intensity is related to wavelength? Could someone people explain to me why this logic is incorrect and why light intensity is not related wavelength? Thank you!

Jessica Johal 2B
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Joined: Fri Sep 29, 2023 10:40 am

Re: Light Intensity and Wavelength

Postby Jessica Johal 2B » Sat Oct 14, 2023 6:00 pm

Light intensity and wavelength are related since they both affect the energy of light but in different ways. Decreasing the wavelength of light increases the energy per photon, while increasing the intensity increases the number of photons per second.

506002081
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Joined: Fri Sep 29, 2023 11:45 am

Re: Light Intensity and Wavelength

Postby 506002081 » Sun Oct 15, 2023 4:01 pm

I think your logic is correct. Adding onto what Jessica said, if you decrease the wavelength of radiation, then the energy per photon will increase, meaning that the intensity of light would also increase. This is because intensity is directly proportional to temperature^4 according to Stefan-Boltzmann's Law. Since wavelength and temperature are inversely proportional (according to Wein's law), this would mean that as wavelength decreases, temperature increases and vice versa. This idea is reinforced because as light intensity increases, temperature increases (this can be seen in Black bodies).


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