A tissue paper soaked with polluted water showed Kα peaks at 78.9 pm, 146 pm, 158 pm and 198 pm. Find the elements it contained.
The frequency (f) of the Kα line is related to the atomic number Z by the following relation:
f=cλ=2.48×1015(Z−1)2Z=1+√cλ×2.48×1015=1+√3×10878.9×10−12×2.48×1015=40,i.e.,ZrZ=1+√3×108146×2.48×10−3=30.1,i.e.,ZnZ=1+√3×108158×2.48×10−3=29,i.e.,CuZ=1+√3×108198×2.48×10−3=26,i.e.,Fe