### Units of De Broglie's Equation

Posted:

**Thu Oct 25, 2018 10:20 pm**I understand that the SI unit for wavelength is meters, but when doing the calculation, how do you cancel the other units to get meters.

Created by Dr. Laurence Lavelle

https://lavelle.chem.ucla.edu/forum/

https://lavelle.chem.ucla.edu/forum/viewtopic.php?f=18&t=34849

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Posted: **Thu Oct 25, 2018 10:20 pm**

I understand that the SI unit for wavelength is meters, but when doing the calculation, how do you cancel the other units to get meters.

Posted: **Thu Oct 25, 2018 10:28 pm**

Since it is h/mv, and J=kg×m^2 the units are:

(kg×m^2)×s/kg×(m×s)

The kg, s, and one m cancel out, leaving only one m on top, which is your unit for wavelength :)

(kg×m^2)×s/kg×(m×s)

The kg, s, and one m cancel out, leaving only one m on top, which is your unit for wavelength :)

Posted: **Thu Oct 25, 2018 10:30 pm**

Lambda=h/mv

Lambda is in meters

h- Planck's constant (6.63x10^(-34))J s or (kg m^2.s^2) s

m-mass in kg

v- velocity in m.s

Everything cancels out so that Lambda, or wavelength, is just in meters.

Lambda is in meters

h- Planck's constant (6.63x10^(-34))J s or (kg m^2.s^2) s

m-mass in kg

v- velocity in m.s

Everything cancels out so that Lambda, or wavelength, is just in meters.

Posted: **Thu Oct 25, 2018 10:31 pm**

Wavelength can also be converted from meters to nanometers and written in that unit.

Posted: **Thu Oct 25, 2018 11:31 pm**

Thanks Guys