A capacitor stores 60µC charge when connected across a battery. When the gap between the plates is filled with a dielectric, a charge of 120µC flows through the battery. The dielectric constant of the material inserted is :
Physics · Capacitor
JEE Mains

Question

A capacitor stores 60µC charge when connected across a battery. When the gap between the plates is filled with a dielectric, a charge of 120µC flows through the battery. The dielectric constant of the material inserted is :

Physics · Capacitor

G1 Physics · Accepted Answer

Use Q = CV, U = ½CV² and C = εA/d; reduce the capacitor network by series/parallel combination and apply charge conservation where a node is isolated. Substituting the given values gives 3.