Electric charge the charge of an electron is negative, "−e", while that of a proton is positive, "+e". Charged particles whose charges have the same sign repel one another, and particles whose charges have different signs attract. Coulomb's law quantifies the electrostatic force between two particles by asserting that the force is proportional to the product of their charges, and inversely proportional to the square of the distance between them. The charge of an antiparticle equals that of the corresponding particle, but with opposite sign. The electric charge of a macroscopic object is the sum of the electric charges of the particles
Imaging particle analysis Imaging particle analysis Imaging particle analysis is a technique for making particle measurements using digital imaging, one of the techniques defined by the broader term particle size analysis. The measurements that can be made include particle size, particle shape (morphology or shape analysis and grayscale or color, as well as distributions (graphs) of statistical population measurements. Imaging particle analysis uses the techniques common to image analysis or image processing for the analysis of particles. Particles are defined here per particle size analysis as particulate solids, and thereby not including atomic or sub-atomic particles. Furthermore, this article is limited to real