Calculating De Broglie Wavelength in Bohr Model

[Jason265]

Homework Statement

In the Bohr model of the hydrogen atom, if the electron is in the second orbit with a radius of 2.12 Å. What is the de Broglie wavelength of the electron?

Homework Equations

λ = 4h^2ε/me^2

The Attempt at a Solution

I found this equation hunting around online and figured out that the constant is 2 times the energy level, but I do not have all of this information. How would I solve this problem?

 

[dextercioby]

What's the connection between the orbit and energy of the electron on that orbit ? Then the energy is simply h$\nu$ from which $\lambda$ is easily derived.