रेशम से रगड़ी गई एक काँच की छड़ को रेशम के धागे से स्वतंत्र रूप से लटकाया जाता है। काँच की ही एक अन्य छड़ को भी रेशम से रगड़कर लटकी हुई छड़ के सिरे के पास लाया जाता है। दोनों छड़ों के बीच क्या प्रतिक्रिया होगी?

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?