We need to consider for this exercise the concept Drag Force and Torque. The equation of Drag force is

Where,
F_D = Drag Force
= Drag coefficient
A = Area
= Density
V = Velocity
Our values are given by,
(That is proper of a cone-shape)



Part A ) Replacing our values,


Part B ) To find the torque we apply the equation as follow,



Answer:
The charge resides on the outer surface =
C
Explanation:
Surface area of cell 
Separation between two plate
Dielectric constant 
Potential difference 
The capacitance of parallel plate capacitor in free space is given by,

Where
permittivity of free space = 
The Capacitance of capacitor is increase by
times when it placed in dielectric medium.

And we know that, 
So charge on the outer surface is given by,



The total work done by the electric field on the charge is given by the scalar product between the electric force acting on the charge and the displacement of the charge:

where the force is F=qE, d=0.556 and

. Using the value of q and E given by the problem, we find