Which one of the following will decrease the capacitance of a parallel plate capacitor?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Increasing the separation between the plates.
The capacitance of a parallel plate capacitor depends only on its geometry (plate area and separation) and the medium between the plates.
\( \displaystyle C = \frac{K\varepsilon_0 A}{d} \)
C is inversely proportional to the separation d, so increasing the separation decreases the capacitance.
NCERT (2026-27):
The Parallel Plate Capacitor – “… The capacitance \( C \) of the parallel plate capacitor is then
\( \displaystyle C = \frac{Q}{V} = \frac{\varepsilon_0 A}{d} \qquad (2.43) \)
which, as expected, depends only on the geometry of the system.”