NEET Physics Question - Capacitors - Parallel Plate Capacitor

Assertion (A): If capacitor is filled with, same thickness \(t < d\) of dielectric and conducting sheet one after another, then capacitance are \(C_1\) and \(C_2\) respectively then \(C_1 < C_2\).

Reason (R): Capacitance is more in presence of metal sheet in compare to dielectric sheet as

(1) Both (A) & (R) are true and the (R) is the correct explanation of the (A)

(2) Both (A) & (R) are true but the (R) is not the correct explanation of the (A)

(3) (A) is true but (R) is false

(4) Both (A) and (R) are false

Solution:

Assertion (A): For a dielectric slab of thickness \(t\) and dielectric constant \(K\), \(C_1 = \frac{\epsilon_0 A}{d-t+t/K}\). For a conducting slab of thickness \(t\), \(C_2 = \frac{\epsilon_0 A}{d-t}\). Since \(K>1\), \(d-t+t/K > d-t\), implying \(C_1 < C_2\). So (A) is true.

Reason (R): A metal (conductor) effectively acts as a dielectric with \(K = \infty\), which makes its capacitance higher than a dielectric with a finite \(K\). So (R) is true and correctly explains (A).

Rankers Physics

Capacitor with Dielectric and Conductor

Solution:

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