आठ विद्युत द्विध्रुव (electric dipoles), जिनमें से प्रत्येक का परिमाण ±e है, एक बंद घन (cube) के अंदर रखे गए हैं। घन से बाहर निकलने वाला कुल विद्युत फ्लक्स कितना होगा?

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?