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### Wavelength of Ejected Electron

Posted: **Tue Oct 04, 2016 10:05 pm**

by **Elle_Bertuccelli_1B**

Hello,

When asked to calculate the wavelength of an ejected electron, do we use the DeBroglie Equation?

I know that it involves finding the wavelength of a moving object and just want to clarify that we aren't supposed to use the lambda=hc/E equation.

Thanks!

### Re: Wavelength of Ejected Electron

Posted: **Tue Oct 04, 2016 10:16 pm**

by **Kathy Vu 3L**

Can I ask what questions you're referring to, because most questions I've seen, ask about the speed of the ejected electron (in which you use the photoelectric effect equation) or what wavelength you need to eject an electron.

### Re: Wavelength of Ejected Electron

Posted: **Wed Oct 05, 2016 11:48 am**

by **Marissa Petchpradub 2F**

I know that you would use the DeBroglie equation when dealing with particles that have a measurable mass, such as an electron. The equations E=hv and lambda=hc/E would be used when dealing with massless particles.

Hope this somewhat helps!

### Re: Wavelength of Ejected Electron [ENDORSED]

Posted: **Wed Oct 05, 2016 6:06 pm**

by **aprilhamachi3B**

You use the De Broglie equation thats lambda = h (planks constant) / p (momentum) because it is used to calculate the wavelength of any object. All matter has wavelike properties but only can be measured if it has a small mass and a high velocity like an electron. So the ejected electron is moving so it has momentum that is used to calculate the wavelength. The equation you stated before (lambda= hc/E) is used to calculate the wavelength of the incident light that caused the electron to be ejected.