Question

If a dielectric is kept between two plates of a capacitor, its capacitance:

• A. Increases
• B. Decreases
• C. First increases then decreases
• D. None of these

Hint:

Inserting a dielectric material between the plates of a capacitor increases its capacitance by a factor equal to the dielectric constant of the material.

Answer 1

The Correct Option is A

Step 1: Understanding the effect of a dielectric.
The capacitance \( C \) of a capacitor is given by the equation: \[ C = \frac{\varepsilon_0 A}{d} \] where \( \varepsilon_0 \) is the permittivity of free space, \( A \) is the area of the plates, and \( d \) is the separation between the plates.
Step 2: Effect of introducing a dielectric.
When a dielectric material with dielectric constant \( \kappa \) is inserted between the plates of a capacitor, the capacitance increases by a factor of \( \kappa \). The new capacitance becomes: \[ C' = \kappa C \] Thus, the capacitance increases when a dielectric is inserted.
Step 3: Conclusion.
Therefore, when a dielectric is inserted between the plates of a capacitor, its capacitance increases, corresponding to option (A).