TRUE The Reynolds number of falling 2.5 micrometer flyash particles in air exceed that of same size of soot particle by more than 50% because the soot particle is a outcome produced due to in complete combustion of carbon particles and very lighter in density compared to the flyash. Solution TRUE The Reynolds number of falling 2.5 micrometer flyash particles in air exceed that of same size of soot particle by more than 50% because the soot particle is a outcome produced due to in complete combustion of carbon particles and very lighter in density compared to the flyash..