Question

In a parallel plate capacitor, if the intervening medium of permittivity $\varepsilon$ between the plates is replaced by another medium of permittivity $\frac{\varepsilon}{2} ,$ then its capacitance is

• A. halved
• B. doubled
• C. unchanged
• D. quadruped

Answer 1

Answer: (A)

halved

Answer 2

The capacitance of a parallel plate capacitor having a medium of permittivity e between the plates is
$C = \frac{\varepsilon A}{d}\,\,\,....(i)$
where $d$ is the distance between the plates and $A$ is the area of each plate.
When the medium of this capacitor is replaced by another medium of permittivity $\frac{\varepsilon}{2}$ then its capacitance becomes
$C' = \frac{\varepsilon}{2} \frac{A}{d}$
$= \frac{1}{2} (\frac{\varepsilon A}{d}) = \frac{C}{2}\,\,\,$ (Using $(i)$)