De Broglie wavelength, velocity of electron

[Sublime74]

Homework Statement

Question 1) Calculate the de Broglie wavelength of a neutron (mn = 1.67493×10-27 kg) moving at one fiftieth of the speed of light (c/50).


Question 2) Calculate the velocity of an electron (me = 9.10939×10-31 kg) having a de Broglie wavelength of 225.7 pm.

Homework Equations

Wavelength of a particle = Plancks constant/(mass)(velocity)
Plancks constant= 6.626068 x 10^-34
I know this, and it should be plug and chug but my answer is always wrong...any help would be greatly appreciated!

The Attempt at a Solution

 

[glueball8]

I got..

1) 2.64*10^-15
2) 3.22*10^6 m/s

what did you get?

 

[mpenny71]

Plug it into

nh/2(pi)m(e-)r(e-)

n= proton number
h= 6.62 x 10^-34
m= e- mass 9.11 x 10^-31 m
r= Bohr radius 5.2 x 10^-11 m