Parallel Plate Capacitors Video Lessons

Concept

# Problem: Two 2.0-cm-diameter disks face each other, 1.0 mm apart. They are charged to ±10 nC.a) What is the electric field strength between the disks?b) A proton is shot from the negative disk toward the positive disk. What launch speed must the proton have to just barely reach the positive disk?

###### FREE Expert Solution

Electric field,

$\overline{)\begin{array}{rcl}{\mathbf{E}}& {\mathbf{=}}& \frac{\mathbf{Q}}{{\mathbf{\epsilon }}_{\mathbf{0}}\mathbf{A}}\end{array}}$

$\overline{){\mathbf{A}}{\mathbf{=}}{\mathbf{\pi }}{{\mathbf{r}}}^{{\mathbf{2}}}}$

###### Problem Details

Two 2.0-cm-diameter disks face each other, 1.0 mm apart. They are charged to ±10 nC.

a) What is the electric field strength between the disks?

b) A proton is shot from the negative disk toward the positive disk. What launch speed must the proton have to just barely reach the positive disk?