Achieve Question 15

[April_Tello_2H]

You use an electron microscope in which the matter wave associated with the electron beam has a wavelength of 0.0231 nm. What is the kinetic energy of an electron in the beam, expressed in electron volts?

I really need help with this question. I know I would have to cover the nm to then have it be (2.31 x 10^-11). I would then use the DeBroglie equation but solve for v in which it would be

v= m*v / Lambda

when plugging in my number I have

(6.626 * 10^-34) / (9.11 * 10 ^-31) (1.29 * 10^-11)

but every time I put it into the calculator I never get an end result ? Is there something wrong with my equation or if not what would the calculation be ?

Please let me know and thank you.

[morgantolbert]

So for this question you would solve for v using the de Broglie equation like you have, but since we are solving for kinetic energy you would also use the kinetic energy = 1/2 mv^2 (mass being the mass of an electron) equation as well to get the kinetic energy of the electron. You would then take that answer and convert it into eV, which I think the conversion is found on our constants and equations sheet. I hope this helps!!