Question #01a9d

1 Answer

You can find the wavelength of the photon the electron emits when it returns.

Explanation:

Once you have the wavelength, use the equation

#E = (hc)/lamda#

to find the energy, where #h# is Planck's constant #(6.626 xx 10^(-34)# #"J s")#, #c# is the speed of light #("300,000,000 m/s")#, and #lamda# (upside down y) is the wavelength.