Q 12.8 In Millikan’s experiment, oil droplets are introduced into the space between two flat horizontal plates, 500 mm apart. The plate voltage is adjusted to exactly 780 Volts so that the droplet is held stationary. The plate voltage is switched off and the selected droplet is observed to fall a measured distance of 1.50 mm in 11.2 s. Given that the density of the oil used is 9000kgm(-3), and the viscosity of air at laboratory temperature is 1.8 * 10(-5) Nm(-2)s, calculate:
(a) the mass, and
(b) the charge on the droplet (assume g = 9.8 ms(-2))