Velocity of atomic (hydrogen) electrons

[nuby]

Hello,

I've been wondering about the velocity of hydrogen electrons. I've read that 242,000 m/s was the correct velocity, however, I thought electrons would travel at c. How does one calculate this number?

Thanks in advance.

 

[malawi_glenn]

Why would/should electrons travel at c?

One can measure/calculate the mean momentum & kinetic energy of the atomic electron, then it is trival to obtain its velocity.

 

[pam]

mv^2=27 eV, so v/c=\sqrt{27/500,000}

 

[nuby]

Can you explain that equation, if you get a chance? Why does mv^2=27ev
Thanks.