# Speed of the Electron

Good evening!

The question states: 9. Electron in bound orbit about proton. Suppose that an electron moves in a circular orbit about a proton at a distance of 2 X l0^-8 cm. Consider the proton to be at rest. (a) Solve for the velocity of the electron by equating the centrifugal and electrostatic forces.

Considering that the elementary charge (charge of the electron is e = 4.8 x 10^-10 statcoloumbs), working on the cgs system, I equated the centrifugal force Fc=v²/r and the eletrostatic force Fe= e²/r². My way of solving the problem was:

Fc=Fe,
v²/r = e²/r²
v²= e²/r
v= (e²/r)¹/²
v= (2.3x10^-19/2x10^-8)¹/²
v = 11.5x10^-6 cm/s.

Thanks!

Orodruin
Staff Emeritus
Homework Helper
Gold Member
Fc=v²/r
Is the electron mass 1 g? Always write out the units!

mjc123