How does the wavelength of light affect its intensity?

AI Thread Summary
The discussion centers on the relationship between light wavelength and intensity in the context of a spectroscopy lab using sodium and mercury. The user initially struggles with the theoretical aspects of electromagnetic wave equations and their connection to intensity. They reference key equations, including the energy of a photon and its relationship to power and photon count over time. Ultimately, they clarify that the intensity can be derived from the power of emitted photons, considering the geometry of the detection area. The conclusion emphasizes that intensity is directly related to the power output and the characteristics of the emitted light.
Drax
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hey everyone,

Homework Statement



I'm doing a sodium and mercury visible light spectroscopy lab at the moment. By using a PMT, I can detect the intensity of photons emitted as a function of wavelength (controlled parameter). I was wondering if anyone knows how the two relate theoretically.

The index of refraction I'm working with is that of air.

Homework Equations



n=sqrt(eps*mu) of air
U=1/2 eps E^2
U is the energy volume density stored by the Efield wave of the light
and E is not the Efield but somehow related to the amplitude.
P=Uv
I=P/A
E=hv?
possibly more?

The Attempt at a Solution



Well, I don't know too much yet about the wave equations describing electromagnetic radiation, but I do know how the de broglie wavelength relates to energy. The first equation I don't really understand in terms of derivation. Furthermore, I'm not sure if U relates to the complex or real amplitude squared of the E field. I'm very comfortable with the de broglie wavelength implications for photons but I'm not sure finding the Schrodinger energy of the photon will get me any closer to finding the power because of the uncertainty equation for energy and time. I'm lost at this point at how to approach relating Intensity to wavelength

Thanks for the help
 
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Nevermind. I figured it out.

For those who ever come across this,
hc/lamda = energy of photon,
but (hc/lamda)*N/T=Power
where N is the photon count and T is the time you count them for.
since A of the spectroscopy detector is far away from the source relative to its magnitude,
the curvature of the sphere of photons emitted is approximately parallel to A. Thus IA=P without worry of a cos term.
 
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