Continuous X-rays are made to strike a tissue paper soaked with polluted water. The incoming X-rays excite the atoms of the sample by knocking out the electrons form the inner shells. Characteristic X-rays are subsequently emitted. The emitted X-rays are analysed and the intensity is plotted against the wavelength (figure 44*E1). Assuming that only `K_alpha` intensities are detected, list the elements present in the sample from the plot. Use Moseley's equation. `v = (25 xx 10^(14) Hz) (Z - 1)^(2)`.