Capacitors & Capacitance Video Lessons

Concept

# Problem: Dry air will break down if the electric field exceeds about 3.0x106 V/mPart AWhat amount of charge can be placed on a capacitor if the area of each plate is 8.6 cm2?Express your answer using two significant figures.

###### FREE Expert Solution

Charge:

$\overline{){\mathbf{Q}}{\mathbf{=}}{\mathbf{C}}{\mathbf{V}}}$

Capacitance:

$\overline{){\mathbf{C}}{\mathbf{=}}\frac{{\mathbf{\epsilon }}_{\mathbf{0}}\mathbf{A}}{\mathbf{d}}}$

Voltage:

$\overline{){\mathbf{V}}{\mathbf{=}}{\mathbf{E}}{\mathbf{d}}}$

Substituting:

$\begin{array}{rcl}\mathbf{Q}& \mathbf{=}& \left(\frac{{\epsilon }_{0}A}{d}\right)\mathbf{\left(}\mathbf{E}\mathbf{d}\mathbf{\right)}\\ & \mathbf{=}& {\mathbf{\epsilon }}_{\mathbf{0}}\mathbf{A}\mathbf{E}\end{array}$

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###### Problem Details

Dry air will break down if the electric field exceeds about 3.0x106 V/m

Part A

What amount of charge can be placed on a capacitor if the area of each plate is 8.6 cm2?