What Are the Formulas for Calculating Photon Momentum and Work Function?

In summary: It might be de Broglie's wavelength though. In summary, the He-Ne gas laser produces red light with a wavelength of 6.3 x 10-7. The momentum of each photon on reflection is changed.
  • #1
Procrastinate
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1. Is binding energy equivalent to work (W)?

2. A He-Ne gas laser produces monochromatic red ligth with a wavelength of 6.3 x 10-7. If the beam is reflected normally from a mirror, what is the change in momentum of each photon on reflection?

I am particularly confused about this question. I used delta p = m(v - u) where v was the speed of light but it didn't result in the correct answer. Could anyone please give me a hint?

I also couldn't figure out what the mass of a photon was so I used the mass of an electron which I am sure is wrong.
 
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  • #2
Procrastinate said:
1. Is binding energy equivalent to work (W)?

Is this work, or "work function"?

2. A He-Ne gas laser produces monochromatic red ligth with a wavelength of 6.3 x 10-7. If the beam is reflected normally from a mirror, what is the change in momentum of each photon on reflection?

I am particularly confused about this question. I used delta p = m(v - u) where v was the speed of light but it didn't result in the correct answer. Could anyone please give me a hint?

I also couldn't figure out what the mass of a photon was so I used the mass of an electron which I am sure is wrong.

You need to go back and find out the expression for the momentum of light. Hint: it is NOT p=mv!

Zz.
 
  • #3
ZapperZ said:
Is this work, or "work function"?

Work function: E = W + KE



You need to go back and find out the expression for the momentum of light. Hint: it is NOT p=mv!

Zz.

1. I supposed binding energy many the threshold energy that was required to illuminate light.

2. Is it de Broglie's wavelength?: p = c/lambda

I didn't think it was this because the change in momentum is a different formula.
 

1. What is the photoelectric effect?

The photoelectric effect is a phenomenon in which electrons are emitted from a material when it is exposed to light of a certain frequency. This effect was first observed by Albert Einstein and is used in many modern technologies such as solar panels and photodiodes.

2. What is the difference between the photoelectric effect and the photoelectric emission?

The photoelectric effect refers to the emission of electrons from a material when it is exposed to light, while photoelectric emission specifically refers to the emission of electrons from a metal surface due to the photoelectric effect.

3. How does the intensity of light affect the photoelectric effect?

The intensity of light does not affect the photoelectric effect. Instead, it is the frequency of the light that determines whether or not the effect will occur. The higher the frequency of the light, the greater the energy of the photons, and the more likely it is that electrons will be emitted from the material.

4. What is the work function in the context of the photoelectric effect?

The work function is the minimum amount of energy needed for an electron to escape from the surface of a material. It is a characteristic property of each material and is dependent on the material's composition and surface properties.

5. How does the photoelectric effect support the particle theory of light?

The photoelectric effect provides evidence for the particle nature of light, as it can only be explained by considering light as a stream of discrete particles (photons) rather than a continuous wave. This is because the emission of electrons is dependent on the energy of the individual photons, rather than the intensity of the light.

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