Question

A parallel plate air capacitor has capacity ${}^{\prime }{C}^{\prime }$ farad, potential ${}^{\prime }{V}^{\prime }$ volt and energy ${}^{\prime }{E}^{\prime }$ joule. When the gap between the plates is completely filled with dielectric.

• A. Both $V$ and $E$ increase
• B. Both $V$ and $E$ decrease
• C. $V$ decreases, $E$ increases
• D. $V$ increases, $E$ decreases

Answer 1

The correct option is B Both $V$ and $E$ decrease

A parallel- plate capacitor with a dielectric. The electric field is reduced between the plates because the dielectric material is polarized, producing an opposing field. When there is a dielectric, the potential is also reduced because potential is inversely proportional to dielectric $V^{\prime }=\frac{V}{K}$ where $K$ is dielectric constant.