# CHEM

posted by on .

The mass of an electron is 9.11*10^-31kg. If the de Broglie wavelength for an electron in a hydrogen atom is 3.31*10^-10m, how fast is the electron moving relative to the speed of light? The speed of light is 3.00*10^8m/s.

Express your answer numerically as a percentage of the speed of light.

How should this question be worked?
I tried: 0.692% already but it was incorrect.

m=9.11*10^-31 kg
lambda=3.31*10^-10 m
c= 3.00*10^8 m/s

• CHEM - ,

Check you math. I get something like 0.732% if I use 6.626 x 10^-34 J*s for h or 0.733 if I use 6.63 x 10^-34.

• CHEM - ,

thank you..I reworked it & the answer came to: 0.73%.

• CHEM - ,

You should carry it to three places since 9.11, 3.00 and 3.31 have three places.