Suppose that a charged particle of diameter 1.00 micrometer moves with constant speed in an electric field of magnitude 1 x 10^5 newtons per coulomb while acted upon by a drag force of 7.24 x 10^-11 newtons. What is the charge q1 on the particle? Ignore the effects of gravity. Express your answer in coulombs to three significant figures. q1 = 7.25 x 10^-16 C by F = E*q If this charged soot particle is now isolated (that is, removed from the electric field described in the previous part), what will be the magnitude of the electric field due to the particle at distance 1.00 meter from the particle? Now I know this must be incorporated: E = F/q, where F = (1/[4pi*epsilon_0])*[k]*[(q1q2)/(r^2)] But where is the diameter or radius of the particle used? And what is r (1 m?) and q2 (is it the same as q1)? Thanks again.