Chapter 32

Chapter 32

1. Electrostatics, or electricity at rest, involves electric charges, the forces between them, and their behavior in materials

2. The fundamental rule at the base of all electrical phenomena is that like charges repel and opposite charges attract.

3. Electrical forces arise from particles in atoms.

4. The fundamental electrical property to which the mutual attractions or repulsions between electrons or protons is attributed is called charge.

5. The nucleus is composed of protons and neutrons

6. All electrons are identical.

7. Every atom has a positively charged nucleus surrounded by negatively charged electrons.

8. An object that has unequal numbers of electrons and protons is electrically charged.

9. A positive ion has a net positive charge; it has lost one or more electrons.

10. A negative ion has a net negative charge; it has gained one or more extra electrons.

11. Electrons are neither created nor destroyed but are simply transferred from one material to another. This principle is known as conservation of charge.

    • F = G m1(m2)/d squared

12. Coulomb’s law states that for charged particles or objects that are small compared with the distance between them, the force between the charges varies directly as the product of the charges and inversely as the square of the distance between them.

13. F= k q1(q2)/d squared

14. The SI unit of charge is the coulomb, abbreviated C.

15. k = 9,000,000,000 N·m2/C2 or 9.0 × 109 N·m2/C2

16. Newton’s law of gravitation for masses is similar to Coulomb’s law for electric charges.

17. Electrons move easily in good conductors and poorly in good insulators.

18. Materials through which electric charge can flow are called conductors.

19. A substance is classified as a conductor or an insulator based on how tightly the atoms of the substance hold their electrons.

20. Semiconductors are materials that can be made to behave sometimes as insulators and sometimes as conductors.

21. Two ways electric charge can be transferred are by friction and by contact.

22. If a charged object is brought near a conducting surface, even without physical contact, electrons will move in the conducting surface.

23. When we allow charges to move off (or onto) a conductor by touching it, we are grounding it

24. Charge polarization can occur in insulators that are near a charged object.

25. One side of the atom or molecule is induced to be slightly more positive (or negative) than the opposite side.The atom or molecule is said to be electrically polarized.

26. Sanjana Dixit