# A vacuum-insulated parallel-plate capacitor with plate separation...

Introduction: capacitor

More Details: A vacuum-insulated parallel-plate capacitor with plate separation d has capacitance C_0
What is the capacitance if an insulator with dielectric constant \kappa(k) and thickness d/2 is slipped between the electrodes?
Express your answer in terms of the variables d, C_0, and kappa.