Post

Created by @nathanedwards
 at November 1st 2023, 9:49:18 am.

Question:

A parallel-plate capacitor has a plate area of 0.02 m² and a separation distance between the plates of 0.005 m. The space between the plates is filled with a dielectric material with a dielectric constant of 4. Determine the capacitance of the capacitor.

Answer:

The capacitance of a parallel-plate capacitor is given by the formula:

C=ε0εrAd C = \frac{{\varepsilon_0 \cdot \varepsilon_r \cdot A}}{{d}}

where:

  • C C is the capacitance of the capacitor
  • ε0 \varepsilon_0 is the permittivity of free space, approximately 8.85×1012F/m 8.85 \times 10^{-12} \, \text{F/m}
  • εr \varepsilon_r is the relative permittivity (dielectric constant) of the material between the plates
  • A A is the area of each plate
  • d d is the separation distance between the plates

Plugging in the given values:

A=0.02 A = 0.02 \, \text{m²} \ d=0.005m d = 0.005 \, \text{m} \ εr=4 \varepsilon_r = 4

The permittivity of free space ε0 \varepsilon_0 is a fundamental constant and does not change.

Substituting these values into the formula:

C=(8.85×1012F/m)(4)(0.02)0.005m C = \frac{{(8.85 \times 10^{-12} \, \text{F/m}) \cdot (4) \cdot (0.02 \, \text{m²})}}{{0.005 \, \text{m}}}

Calculating the expression:

C=8.85×1012F/m40.020.005m C = \frac{{8.85 \times 10^{-12} \, \text{F/m} \cdot 4 \cdot 0.02 \, \text{m²}}}{{0.005 \, \text{m}}}
C=(8.85×4)×1012+0+2F0.005m C = \frac{{(8.85 \times 4) \times 10^{-12+0+2} \, \text{F}}}{{0.005 \, \text{m}}}
C=35.4×1010F0.005m C = \frac{{35.4 \times 10^{-10} \, \text{F}}}{{0.005 \, \text{m}}}
C=7.08μF C = 7.08 \, \mu \text{F}

Therefore, the capacitance of the parallel-plate capacitor is 7.08 microfarads.