A parallel-plate capacitor is constructed of two horizontal 12.0-cm-diameter circular plates. A 1.1 g plastic bead with a charge of -5.6 nC is suspended between the two plates by the force of the electric field between them. What is the charge on the positive plate?

The charge on positive plate is C

Explanation:

Given :

Diameter m

Radius m

Mass of bead Kg

Charge of bead C

Electric field in capacitor is given by,

Where

For finding electric field in terms of force,

But

        ( )

N

So electric field,

Now charge on positive plate is,

C

Therefore, the charge on positive plate is C