A sheet of bakelite 4.57 mm thick is tested at 50Hz between electrodes 12.10 cm in diameter. Schering bridge employes has a standard compressed air capacitor of 106 pF a non-inductive resistor of 1000/π ohm in parallel with a variable capacitance C, and a non-inductive variable resistor R. Balance is obtained with:
C=0.5μF and R=260 ohm.
Calculate the p.f and the permittivity of the sheet.