Millikan measured the electron's charge by observing tiny charged oil drops in an electric field. Each drop had a charge imbalance of only a few electrons. The strength of the electric field was adjusted so that the electric and gravitational forces on a drop would balance and the drop would be suspended in air. In this way the charge on the drop could be calculated. The charge was always found to be a small multiple of 1.6e19 C. Find the charge on an oil drop weighing 1.70 x 10'14 N and suspended in a downward field of magnitude 2.13 x 104 MC. :15