Data:
Mass of water drop (m)=10mg=10−5kg
Charge, q=1.5×10−6C
As the water drop is balanced in the air, we can say that the
gravitational force of the water drop is balanced by the electric force on the
water drop.
Let the electric field =E
Electric force = weight
Eq=mg
E=mgq
E=(10−5)×9.81.5×10−6
E=65.33N/C
Directed vertically upwards.