PHYSICS · Multi-part · CBSE · Physics · Electrostatic Potential and Capacitance · Electrostatic Potential and Capacitance
Problem
Capacitors C1=10μF and C2=20μF are connected in parallel. This parallel combination is connected in series with a capacitor C3=5μF across a 30V ideal battery. After the capacitors are fully charged, the battery is disconnected from the circuit without discharging the capacitors. A dielectric slab of dielectric constant κ=2 is then completely inserted between the plates of C3, fully filling the gap.
(i) Calculate the charge on each capacitor immediately before the battery is disconnected.
(ii) Determine the new value of the capacitance of C3 after the dielectric is inserted.
(iii) Find the new potential difference across C3 and the common potential difference across the parallel branch containing C1 and C2."
(iv) Compute the total energy stored in the system (a) before and (b) after the insertion of the dielectric. Hence determine the change in energy of the system.