Question

The function of a dielectric in a capacitor is

• A. to reduce the effective potential on plates.
• B. to increase the effective potential on plates.
• C. to decrease the capacity of capacitance.
• D. to reduce the plate area of the capacitor.

Hint:

Dielectric constant $K$ always increases capacitance by factor $K$ ($C_{new} = KC_{old}$).

Answer 1

The Correct Option is A

Step 1: Concept
Inserting a dielectric material polarizes the medium, creating an internal electric field that opposes the external field.

Step 2: Analysis
This reduction in the net electric field between the plates leads to a decrease in the potential difference ($V = Ed$) across the plates for the same charge $Q$.

Step 3: Calculation
Since $C = Q/V$, a decrease in potential $V$ results in an increase in the capacitance $C$.

Step 4: Conclusion
Hence, the primary function is to reduce the effective potential on the plates to allow more charge storage. Final Answer: (A)