Eduprobe
Question:
A parallel plat capacitor is made of two circular plates separated by a distance of 5mm and with a dielectric of dielectric constant 2.2 between them. When the electric field in the dielectric is 3 × 10⁴ V/m, the charge density of the positive plate will be close to:
6 × 10⁻⁵ C/m²
6 × 10⁴ C/m²
3 × 10⁻⁵ C/m²
3 × 10⁴ C/m²
Solution:
Answer is C.
By formula of electric field between the plates of a capacitor
E = σ/Kε₀
σ = EKε₀ = 3 × 10⁴ × 2.2 × 8.85 × 10⁻¹⁴ = 6.6 × 8.85 × 10⁻¹⁰ = 5.841 × 10⁻⁹ ≈ 6 × 10⁻⁹ C/m²