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### Question 1.B.15 7th

Posted: **Tue Oct 23, 2018 7:09 pm**

by **1K Kevin**

Can someone help me with part A. Its given "the velocity of an electron is emitted from a metal surface by a photon is 3.6 x 10^3 km * s^-1 and are trying to find the wavelength of the ejected electron" Im having a hard time figuring out what equations to use or the steps to solving it. Thanks!

### Re: Question 1.B.15 7th

Posted: **Tue Oct 23, 2018 7:35 pm**

by **Jonas Talandis**

Hi,

Since electrons have wave-particle duality, you can use the De Broglie equation for this, inserting the velocity into the calculation for p. Hope that helps!

### Re: Question 1.B.15 7th

Posted: **Wed Oct 24, 2018 5:10 pm**

by **Jamie Hsu**

Use the DeBroglie wavelength equation and plug into the numerator Planck's constant. In the denominator you can multiply the mass of an electron (9.11x10^-31 kg) by the velocity which is 3.6x10^6 ms-1. This should give you the desired answer of 2.02 x 10^-10 meters.