1. (i) Graph the saturation ratio curve for a (NH4)2SO4 particle with the dry nucleus mass of 10-15 g. Determine the critical size (rc) and the critical supersaturation in (Sc - 1)% for the particle to activate to form a cloud droplet. (ii) Consider two (NH4)2SO4 aerosols with the radii of r1 and r2 and with the same dry particle size as in (i). The two particles are both in equilibrium with the ambient water vapor and r1 < rc < r2 where rc is the critical radius. If both particles undergo a coagulation with a 0.001 m pure water droplet, what are the microphysical states of the particles and explain the similarity or difference in the microphysical states of the two particles in terms of the Kevin and solution effects.