Scattering light by homogenous metal nanoparticles with spheric shape was studied. The diffusion efficiencies Qext and Qabs were found using Mie theory. We employed a MATLAB code to calculate the Mie efficiencies and the radial dependence of electric field intensities. Also we investigated the electric field intensities produced by Co and Ni nanoparticles (NP's) of diferents diameters moving under Brownian motion and the relation with localized plasmons resonances in NP's was determined.