Relationship between light wavelength, intensity and photons energy

[techguy]

Hi peeps,

i am having a project and i wish to clear some concept.

1. The shorter the wave length the higher the photon energy? Am i right?

2. The higher the intensity of light, the higher amount of photons exist in the light? Am i right?

3. So higher intensity plus short wave length will give a lot of overall energy in the light? Am i right?

Thanks!

 

[Hootenanny]

Hi peeps,

i am having a project and i wish to clear some concept.

1. The shorter the wave length the higher the photon energy? Am i right?

Correct

2. The higher the intensity of light, the higher amount of photons exist in the light? Am i right?

Spot on again

3. So higher intensity plus short wave length will give a lot of overall energy in the light? Am i right?

Yup.

 

[techguy]

Ok thanks! So here goes another question since my basic concept is correct...

so does that means that higher intensity plus short wavelength light, it will generate much more voltage and current as compared to same amount of intensity plus high wavelength light in photovoltaic cell?

 

[benj]

No this is not neccessarily true.

This is mostly down to a couple of reasons...

1. The general rule is one photon will be converted to one electron and the energy of this photon is not related to the energy the electron will deliver in terms of current and voltage (the exception to this case being down conversion solar cells where a high energy electron may be converted into two low energy electrons).

2. The solar cell will respond differently to different wavelengths of light. Higher energy photon does not neccessarily mean more likely to be converted into a photon.

 

[rwisz]

Hello there,

I can confirm that your understanding of the relationship between light wavelength, intensity, and photon energy is correct. Let me explain in more detail:

1. The shorter the wavelength of light, the higher the energy of the photons. This is because the wavelength of light is inversely proportional to its frequency, and energy is directly proportional to frequency according to the equation E=hf, where h is Planck's constant. Therefore, shorter wavelengths have higher frequencies and thus, higher energy photons.

2. Yes, the higher the intensity of light, the higher the number of photons present in the light. Intensity is a measure of the amount of energy passing through a given area in a given time, so a higher intensity means more photons are present.

3. Correct, combining a short wavelength and high intensity of light will result in a large amount of overall energy in the light. This is why shorter wavelength, high intensity light sources such as X-rays and gamma rays are used in medical imaging and radiation therapy.

I hope this helps clarify your concept and good luck with your project!