Questions about the Photoelectric Effect

[Kidphysics]

Thought to put this here because of the wave-particle duality ties. My question, that I already asked a tutor was how come electron ionization is due to frequency, and not intensity.

He told me that it was because of nature's "no free lunch" policy and that changing the intensity was just adding two distinct waves constructively. My question was that since the two different waves are going to occupy the same space wouldn't the photon, or the single photon wave's total energy increase as a whole? Why doesn't the change in INTENSITY not enough for the photoelectric effect? Thank you.

 

[matonski]

Increasing the intensity just means increasing the number of photons. Each will still have the same energy.

 

[Kidphysics]

Increasing the intensity just means increasing the number of photons. Each will still have the same energy.

thank you for your answer, but what about increasing the wave's amplitude? Doesn't a bigger amplitude= more energetic wave? Or does high amplitude also just mean more photons (in one area) and this was what my tutor was trying to say. If it is I have one remaining question. Thanks in advance for the help.

 

[matonski]

Bigger amplitude just means more photons also, since intensity is the square of the amplitude. More photons means a more energetic wave. But again, each photon still has the same energy.

 

[Kidphysics]

Bigger amplitude just means more photons also, since intensity is the square of the amplitude. More photons means a more energetic wave. But again, each photon still has the same energy.

If two photon waves were to "construct" why can we not think of this new wave as a single photon wave? Why do we say that this single wave with a large amplitude is "many photons? If we were to draw it, would it not be conglomerated into one single wave?

Construction is a wave property, so, I'm guessing that photons CAN construct into a single entity- a single high energy wave, but since in this experiment the individual photons are retaining their individual energies they aren't "meshing" and they are behaving like particles. Is this correct?

 

[Joseph14]

If two photon waves were to "construct" why can we not think of this new wave as a single photon wave? Why do we say that this single wave with a large amplitude is "many photons? If we were to draw it, would it not be conglomerated into one single wave?

Construction is a wave property, so, I'm guessing that photons CAN construct into a single entity- a single high energy wave, but since in this experiment the individual photons are retaining their individual energies they aren't "meshing" and they are behaving like particles. Is this correct?

The wave will be absorbed only one quanta of energy (or photon) at a time so having a bigger wave won't make a difference. Maybe what your getting at is that if two photons were absorbed by the same electron then it could be ionized even though the frequency is incorrect. This may be possible but it would be like getting hit by lighting twice.

 

[Kidphysics]

Maybe what your getting at is that if two photons were absorbed by the same electron then it could be ionized even though the frequency is incorrect.

Okay this answer (with the others) helps me to conclude my confusion.

Obviously the photoelectric effect is dealing with quanta of energy or photons in their particular form.

I thought that possibly the electron could be hit by both photons- if they were to mesh into a constructive wave- where they could 'strike' the electron at the same time. I know this meshing is a wave property, and I've learned that when we are talking about a photon wave with a high amplitude, or a photon wave with high intensity, that we are actually talking about a conglomerate wave of individual photons. Yes?

 

[matonski]

Yes. Roughly, the amplitude squared is equal to the density of photons. Two waves can interfere and create a larger amplitude, but that just means more photons.