Question

Calculate the wavelength of the photon emitted when an electron makes a transition from n=5 to n=3. You can make use of the following constants: h=6.626×10−34 J⋅s c=2.998×108 m/s 1 m=109 nm

Answer 1

Apply Rydberg Formula

E = R*(1/nf^2 – 1/ni ^2)

R = -2.178*10^-18 J

Nf = final stage/level

Ni = initial stage/level

E = Energy per unit (i.e. J/photon)

E = (-2.178*10^-18)*(1/5^2 – 1/3 ^2)

E = 1.5488*10^-19 J/photon

For the wavelength:

WL = h c / E

h = Planck Constant = 6.626*10^-34 J s

c = speed of particle (i.e. light) = 3*10^8 m/s

E = energy per particle J/photon

WL = ( 6.626*10^-34)(3*10^8)/(1.5488*10^-19 ) =0.00000128344 m

WL = 0.0000012834*10^9 = 1283.4 nm