A parallel-plate capacitor, with air in between the plates, has capacitance C. Now the space between the two plates of the capacitor is filled with a dielectric of dielectric constant 7. Then the value of the capacitance will become
C
C/7
7C
14C
Answer is Right!
Answer is Wrong!
This question was previously asked in
UPSC CDS-1 – 2017
The capacitance of a parallel-plate capacitor is given by C = ε * A / d, where ε is the permittivity of the material between the plates, A is the area of the plates, and d is the distance between them. When there is air (or vacuum) between the plates, the permittivity is approximately ε₀, and the capacitance is C = ε₀ * A / d. When the space is filled with a dielectric material of dielectric constant κ, the permittivity changes to ε = κ * ε₀. Therefore, the new capacitance C’ becomes C’ = (κ * ε₀) * A / d = κ * (ε₀ * A / d). Given that the dielectric constant κ = 7, the new capacitance is C’ = 7 * C.