## Usage of E=hv

Wasila Sun 1K
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### Usage of E=hv

Does the E=hv and E=hc/wavelength equation only work for the energy of an incoming photon and not the energy of the emitted electron?

Chem_Mod
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### Re: Usage of E=hv

Use the equations that you listed for an incoming photon. Use DeBroglie's for electrons!

Kyle Walsh 1K
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### Re: Usage of E=hv

Hi! I'm pretty sure that E=hv is a universal equation that works whether the electron is emitted or incoming, but many problems phrase it as an incoming electron because that is how it is perceived to monitoring devices in a lab.

Jeffrey Doeve 3H
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### Re: Usage of E=hv

I agree! One way to think of it is that photons do not have a mass, which is why you have to use those equations. On the other hand, electrons/neutrons/protons are particles and have a mass, so they can be expressed through the De Broglie Wavelength function(Has a mass in the denominator)!

George_Yin_3I
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Joined: Wed Sep 30, 2020 9:42 pm

### Re: Usage of E=hv

For electrons, you can use De Broglie's equation,
which is wavelength lambda=h divided by p, in which p=mv.

Catherine Bubser 2C
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### Re: Usage of E=hv

Would the question have to explicitly state that we are solving for the energy of incoming photon in order to use c=lambda(v) ? Is there another key word that would point to using an equation for a particle with no mass?

John_Tran_1L
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### Re: Usage of E=hv

To compute the energy of an incoming photon use E=hv, De Broigle's equation is used for electrons.

Ven Chavez 2K
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### Re: Usage of E=hv

Because photons do not have mass, you would use the equation E=hv. You would use De Broglie's for electrons, neutrons, and protons.

Brandon Gruender 1L
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### Re: Usage of E=hv

Yes this is used for photons as there is no mass, but when there is mass (an electron has a constant mass listed on the constants sheet) then you use DeBroglie's equation to solve for wavelength. Hope this helped!

Austin Aldujaili 2E
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Joined: Wed Sep 30, 2020 9:46 pm

### Re: Usage of E=hv

Since electrons have a mass, using E=hv to calculate the energy of an electron would be incorrect. As everyone else has said, use DeBroglie's Equation to calculate speed, then KE of an electron.

Edwin Liang 2I
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Joined: Wed Sep 30, 2020 9:34 pm

### Re: Usage of E=hv

Those equations work for photons. De Broglie's equation is for electrons.