The Kα X-rays of aluminum (Z = 13) and zinc (Z = 30) have wavelengths 887 pm and 146 pm respectively. Use Moseley’s law √v = α (Z – b) to find the wavelength of the Kα X-ray of iron (Z = 26).
Given:
Kα X-rays of zinc and aluminum have wavelengths, respectively
By using the formula
frequencies of Kα X-rays of zinc and aluminum, respectively are
Using Moseley’s law √v = α (Z – b),
for Aluminum,
for Zinc,
Dividing equations 1 by 2,
solving. we get
b=
Therefore
a =
for Fe(Iron), Frequency is given by
By using the formula
wavelength of Kα X-rays given out by Iron atom is given by