MCQ
The potential difference between the two plates of a parallel plate capacitor is constant. When air between the plates is replaced by dielectric material, the electric field intensity:
- ✓Decreases
- BRemains unchanged
- CBecomes zero
- DIncreases
✓
Answer
Correct option: A.
Decreases
In general capacitance of parallel plate capacitor is given by:
$\text{C}=\frac{\text{K}\in_0\text{A}}{\text{d}}$
Where $C$ is capacitance, k is relative permittivity of dielectric material, $\epsilon_0$ is permittivity of free space constant, A is area of plates and d is distance between them. Therefore, the capacitance of parallel plates is increased by the insertion of a dielectric material. Further, the capacitance is inversely proportional to the electric field between the plates, and hence the presence of the dielectric decreases the effective electric field.
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