Energy of Photon
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Energy of Photon
If trying to find the longest wavelength possible when given the work function -- how do you solve for the energy of the photon and why do we care what the energy of the photon is if in this instance we would assume KE = 0?
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Re: Energy of Photon
Since the Kinetic energy is equal to zero, We can assume the work function is equal to the actual energy of the Photon. This means we can use the work function to find the wavelength. (Use work function as if it was the Energy of the Photon)
Given formula:
E= hc / (wavelength)
Derived Formula to get wavelength.
wavelength = hc / E
Kinetic Energy + Work function = Energy (Photon)
0 + Work Function = Energy
Given formula:
E= hc / (wavelength)
Derived Formula to get wavelength.
wavelength = hc / E
Kinetic Energy + Work function = Energy (Photon)
0 + Work Function = Energy
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Re: Energy of Photon
In order to find the energy of a photon, you would use this equation: E(photon) = work function + Kinetic Energy. Using E= hc/lambda, you would be able to calculate the work function, or the amount of energy used to eject an electron. Since you already know the kinetic energy is equal to 0, the energy of the photon would be equal to the work function you just calculated. Hope this helped!
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Re: Energy of Photon
If the kinetic energy = 0, that means that the work function is equal to the energy of the photon.
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Re: Energy of Photon
Hi,
Conceptually, the work function (threshold energy) is the minimum energy required to eject electrons from the metal surface. Because electrons interact with photons on a 1:1 basis, the work function is the minimum energy that each photon of the light source must possess to perform electron ejection. It is important to remember that the wavelength of electromagnetic radiation (light) is inversely proportional to its frequency and energy per photon. In other words, as the energy per photon decreases, the frequency of the electromagnetic radiation decreases and the wavelength of the electromagnetic radiation increases. When the question asks to calculate the longest wavelength, it is referring to the work function (threshold energy), as it is the lowest energy per photon that can eject electrons. Therefore, you just need to set the energy per photon equal to the work function to calculate the frequency of the electromagnetic radiation, and then use c = λ*v to calculate its corresponding wavelength:
E(photon) = ϕ
h*v = ϕ
v = ϕ / h
c = λ*v
λ = c / v
λ = c / (ϕ / h)
Hope this helps!
Conceptually, the work function (threshold energy) is the minimum energy required to eject electrons from the metal surface. Because electrons interact with photons on a 1:1 basis, the work function is the minimum energy that each photon of the light source must possess to perform electron ejection. It is important to remember that the wavelength of electromagnetic radiation (light) is inversely proportional to its frequency and energy per photon. In other words, as the energy per photon decreases, the frequency of the electromagnetic radiation decreases and the wavelength of the electromagnetic radiation increases. When the question asks to calculate the longest wavelength, it is referring to the work function (threshold energy), as it is the lowest energy per photon that can eject electrons. Therefore, you just need to set the energy per photon equal to the work function to calculate the frequency of the electromagnetic radiation, and then use c = λ*v to calculate its corresponding wavelength:
E(photon) = ϕ
h*v = ϕ
v = ϕ / h
c = λ*v
λ = c / v
λ = c / (ϕ / h)
Hope this helps!
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