Question

calculate the voltage needed to balance on oil drop carrying 10e when located b/w the plates of a capacitor which are 5mm apart . the mass of oil drop​

Answer 1

The gravitational force on the oil drop = mg = 3 x 10-16 x 10 = 3 x 10-15 N.

Magnitude of the electrostatic force needed balance this force is given by

E = mg/10e = (3 x 10-15) / (10 x 1.6 x 10-19) = 0.1875 x 104 V/m.

Voltage across the places of the capacitor is then given by

V = Ed = 0.1875 x 104 x 5 x 10-3 = 9.375 Volts.

Answer 2

Answer:

F

G

=3×10

−6

×10=3×10

−15

N

E=(

10e

mg

)=(

10×1.6×10

−19

3×10

−15

)=0.1875×10

4

V/m

V=Ed

=0.1875×10

4

×5×10

−3

=9.375volt