Question

What is the electrostatic pressure on the plate of a PPC of capacitance $2\, \mu F$ separated by $2\, mm$ and $20\, V$ potential difference is applied across the capacitor

• A. $2.425 \times 10^{-5} Pa$
• B. $4.425 \times 10^{-4} Pa$
• C. $7.425 \times 10^{-4} Pa$
• D. $1.425 \times 10^{-5} Pa$

Answer 1

Answer: (B)

$C =2\, \mu F$
$d =2\, mm$
$V =20\, v$
$P =\frac{ F }{ A }=\frac{\sigma^{2}}{2 \varepsilon_{0}}=\frac{1}{2} \in E ^{2}$
Where $E =\frac{ V }{ d }$
$=\frac{1}{2} \in_{0} \frac{ v ^{2}}{ d ^{2}}$
$=\frac{1}{2} \times 8.85 \times 10^{-12} \times \frac{400}{4 \times 10^{-6}}$
$P =4.425 \times 10^{-4} Pa$