यदि कांच की एक छड़ को रेशम के कपड़े से रगड़ा जाता है और एक फूले हुए रबर के गुब्बारे को ऊनी कपड़े से रगड़ा जाता है, तो कौन सा विकल्प उन सामग्रियों की सही पहचान करता है जो ऋण आवेश (negative charge) प्राप्त करती हैं?

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?