Question

A capacitor consists of two metal plates each $10cm$ by $20cm;$ they are separated by a $2.0mm$ thick insulator with dielectric constant $4.1$ and dielectric strength 6.0107 V/m. What is the capacitance in $pF\left({10}^{-12}F\right)?$

• A. 75
• B. 100
• C. 240
• D. 360

Answer 1

Answer: (D)

$C=\frac{k{ϵ}_{0}A}{d}$

$C=\frac{4.1\times 8.85\times {10}^{-12}\times 10\times 20\times {10}^{-4}}{2\times {10}^{-3}}$

$C=361\approx 360pF$