PHYSICS · Subjective · CBSE · Physics · Electrostatic Potential and Capacitance · Electrostatic Potential and Capacitance
Problem
Three identical parallel-plate capacitors, each of initial capacitance C0, are connected in parallel to a battery of emf V. After the arrangement attains steady state with air between all plates, the battery remains connected while a dielectric slab of relative permittivity κ is completely inserted between the plates of one of the capacitors only.
(a) Determine qualitatively how the equivalent capacitance of the combination changes and explain why.
(b) Find the new charge stored on each of the three individual capacitors in terms of C0, κ and V.
(c) Show that the total energy stored in the system after the insertion is greater than the energy stored before insertion, and obtain an expression for the factor by which it increases.
(d) Explain the physical origin of the extra energy appearing in part (c).