Sapling #1

[Arezo Ahmadi 3J]

Hi, I was confused on this question: Consider a single photon with a wavelength of , a frequency of , and an energy of E. What is the wavelength, frequency, and energy of a pulse of light containing 100 of these photons?

I was confused on the part of this question in which 100 is not supposed to be applied to the wavelength and frequency, but instead only the energy. I thought that if there are 100 photons, then the wavelength and frequency would also be affected, but why is it not? What part of the Einstein equation can show this direct relationship and what other relationships show that only energy would be affected?

Thank you in advance!

[Jason Nguyen_1B]

The reason why wavelength and frequency is not affected by the number of photons is because each photon has its own specific wavelength and frequency. If one photon has wavelength λ and frequency v, then in 100 photons, the wavelength and frequency will be the same since each photon has the same wavelength and frequency. However for the energy of the photon, energy is given in joules per photon. Since there are 100 photons, that means that the energy will be 100E.

[Jessie Hsu 1C]

The equation E = h* frequency gives energy in the unit J/photon, so even though there are 100 photons, all of them have the same frequency and thus wavelength. The photons don't affect each other, but with 100 photons together, the total energy would be E*100 photons. Hope this helps!

[Dane_Beasley_1E]

The equation E=hv gives the energy per photon. So that's why it is 100E. Wavelength and frequency are not affected because each photon would have its own frequency and wavelength. Since each photon has the same energy, they would have the same wavelength and frequency keeping it a 1.

[TiffanyBrownfield 2I]

Yes, when you have 100 photons with the same wavelength and frequency (wavelength and frequency are inversely proportional), then the only thing that would change would be the intensity (amplitude) of the EM radiation. This also affects the amount of energy. The wavelength/frequency are specific to each individual proton and are not added/combined. You could think of it this way, if you were to shine multiple flashlights in the same direction, the light would become brighter with each flashlight you use. Thus, the energy is increasing. If the frequency/wavelength were to be affected by this, then that would theoretically make it possible to create a different kind of EM radiation (like X-rays or gamma rays) from using a lot of flashlights. That's why the frequency and wavelength were not affected by the number of protons. I hope that makes sense.

[George Hernandez 3I]

Remember that the wavelength and the corresponding frequency is a characteristic of the photon, and that having more of these photons will not affect this individual aspect.

Think of it like horses pulling a wagon. If you add more horses, the 'intensity' of the wagon being pulled increases, but the individual horses' strengths aren't changed.

[Jacob Schwarz-Discussion 3I]

It's 100E because there are 100 photons-each photon adds more energy-therefore 100E