Final answer:
The charge on the oil drop in the Millikan's oil-drop experiment is 1.9 x 10-19 C.
Step-by-step explanation:
In Millikan's oil-drop experiment, the charge on the drop can be determined using the equation:
q = mg/E
Where:
- q is the charge on the drop
- m is the mass of the drop
- g is the acceleration due to gravity
- E is the electric field between the plates
Plugging in the given values, we have:
q = (1.9 x 10-14 N)/(780 V/0.063 m)
q = 1.9 x 10-19 C
Therefore, the charge on the drop is 1.9 x 10-19 C.