दो परावैद्युत पट्टियाँ, जिनके परावैद्युतांक क्रमशः K1 और K2 हैं तथा मोटाई क्रमशः d4 और 3d4 हैं, d दूरी और A क्षेत्रफल वाली संधारित्र प्लेटों के बीच रखी जाती हैं। इस निकाय की कुल धारिता क्या है? (ε0 निर्वात की विद्युतशीलता है):

Which of the following statements are correct regarding electrostatic properties of conductors? A. Inside a conductor, the electrostatic field is zero. B. Electric field at the surface of a charged conductor does not depend on its surface charge density. C. The interior of a charged conductor can have no excess charge in static conditions. D. At the surface of a charged conductor, the electrostatic field must be normal to the surface at every point. E. The electrostatic potential is zero everywhere inside a charged conductor. Choose the correct answer:

What type of electric charge is acquired by a glass rod when it is rubbed with a silk cloth?