المجلة الدولية للعلوم والتقنية

In this research, a theoretical study and laboratory experiments were conducted to know the relationship of the transmission of helium-neon laser rays with power (2mW) and wavelength of 632nm at different depths through the water medium for several types of water (ground water, rain water and other types of locally bottled water (al-nabaa, Dajala and Al-Waha)) and the amount of transmittance of these rays, which naturally the case is directly related to the so-called attenuation coefficient. The decrease in permeability was observed with increasing the depth of the penetrating path for all water samples under study,This decrease is the product of the scattering of the ray with water molecules [1] As well as the product of absorption by water molecules.but with different values, and this difference is the indicator that indicates the attenuation coefficient and thus the extent of water purity. It was found through this study that the water of Dajla is more pure, it has the lowest attenuation coefficient ( 0.005cm-1) in the samples under study but the groundwater has Lowest purity in all samples which means highest attenuation coefficient value (0.04cm-1) .