Usage of E=hv


Moderators: Chem_Mod, Chem_Admin

Wasila Sun 1K
Posts: 44
Joined: Wed Sep 30, 2020 10:00 pm
Been upvoted: 2 times

Usage of E=hv

Postby Wasila Sun 1K » Fri Oct 23, 2020 12:44 pm

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
Posts: 18891
Joined: Thu Aug 04, 2011 1:53 pm
Has upvoted: 716 times

Re: Usage of E=hv

Postby Chem_Mod » Fri Oct 23, 2020 12:46 pm

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

Kyle Walsh 1K
Posts: 31
Joined: Wed Sep 30, 2020 9:48 pm

Re: Usage of E=hv

Postby Kyle Walsh 1K » Fri Oct 23, 2020 12:48 pm

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
Posts: 39
Joined: Wed Sep 30, 2020 9:51 pm

Re: Usage of E=hv

Postby Jeffrey Doeve 3H » Fri Oct 23, 2020 12:48 pm

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
Posts: 39
Joined: Wed Sep 30, 2020 9:42 pm

Re: Usage of E=hv

Postby George_Yin_3I » Fri Oct 23, 2020 10:30 pm

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

Catherine Bubser 2C
Posts: 40
Joined: Wed Sep 30, 2020 9:45 pm

Re: Usage of E=hv

Postby Catherine Bubser 2C » Sat Oct 24, 2020 10:40 am

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
Posts: 44
Joined: Wed Sep 30, 2020 9:58 pm

Re: Usage of E=hv

Postby John_Tran_1L » Sat Oct 24, 2020 11:21 am

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

Ven Chavez 2K
Posts: 35
Joined: Mon Feb 24, 2020 12:16 am

Re: Usage of E=hv

Postby Ven Chavez 2K » Sat Oct 24, 2020 1:23 pm

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
Posts: 35
Joined: Wed Sep 30, 2020 10:03 pm

Re: Usage of E=hv

Postby Brandon Gruender 1L » Sat Oct 24, 2020 2:07 pm

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
Posts: 42
Joined: Wed Sep 30, 2020 9:46 pm

Re: Usage of E=hv

Postby Austin Aldujaili 2E » Sat Oct 24, 2020 3:44 pm

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
Posts: 34
Joined: Wed Sep 30, 2020 9:34 pm

Re: Usage of E=hv

Postby Edwin Liang 2I » Sun Oct 25, 2020 5:14 pm

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


Return to “Einstein Equation”

Who is online

Users browsing this forum: No registered users and 1 guest