The heating rate of particles in a fluid depends on: (i) the relative conductivities of the system’s phases and (ii) the relative volume of those phases. Low conductivity solid particles,comparatively to the fluid conductivity, tend to lag behind the fluid at low concentrations related to the volume of the fluid. However, in conditions where the concentration of the particles is high, those same low conductivity particles may heat faster than the surrounding fluid. So, the phenomenon of particle-lagging or particle-leading depends on the significance of particle resistance to the overall circuit resistance. This phenomenon occurs because, with the increase of the particles’ concentration, the electric current path through the fluid becomes more tortuous, forcing a greater percentage of the current to flow through the particles. This can result in higher energy generation rates within the particles and consequently in a greater relative particle heating rate. This fact indicates that it may be possible to adjust the heating pattern of solid-fluid systems by adjusting the overall influence of particles’ resistance in the system through setting the particles concentration in the fluid.