Each plate of an air-filled parallel-plate air capacitor has an area of 0.0040 m², and the separation of the plates is 0.080 mm. An electric field of 5.3 × 10⁶ V/m is present between the plates. What is the energy density between the plates? (ε0 = 8.85 × 10^-12 C²/N ∙ m²) A) 124 J/m³ B) 84 J/m³ C) 170 J/m³ D) 210 J/m³ E) 250 J/m³

Question

Quizplus · Accepted Answer

The energy density between the plates of a parallel-plate capacitor is given by:$$u = \frac{1}{2}ε_0E^2$$where:* u is the energy density in J/m^3* ε0 is the permittivity of free space in C^2/N ∙ m^2* E is the electric field strength in V/mPlugging in the given values, we get:$$u = \frac{1}{2}(8.85 × 10^{-12} C^2/N ∙ m^2)(5.3 × 10^6 V/m)^2 = 124 J/m^3$$Therefore, the correct answer is A.

Each Plate of an Air-Filled Parallel-Plate Air Capacitor Has an Area