A spherical water drop $1.20 \mu \mathrm{m}$ in diameter is suspended in calm air due to a downward-directed atmospheric electric field of magnitude $E=462 \mathrm{~N} / \mathrm{C}$. What is the magnitude of the gravitational force on the drop?
$8.87 \times 10^{-15} \mathrm{~N} $