Week 1: Introduction, Electric Charge properties, Conductors and Insulators, Charge Quantization, Charge Conservation, Check points, Questions

In dry weather, you can produce a spark by walking across certain types of carpet and then bringing one of your fingers near a metal doorknob, metal faucet, or even a friend. You can also produce multiple sparks when you pull, say, a sweater from your body or clothes from a dryer. Sparks and the "static cling" of clothing are usually just annoying. However, if you happen to pull off a sweater and then spark to a computer, the results are more than just annoying. These examples reveal that we have electric charge in our bodies, sweaters, carpets, doorknobs, faucets, and computers. In fact, every object contains a vast amount of electric charge.

After reading this chapter, you should be able to . . .

  1. Distinguish between being electrically neutral, negatively charged, and positively charged and identify excess charge.
  2. Distinguish between conductors, nonconductors (insulators), semiconductors, and superconductors.
  3. For either of the particles in a pair of charged particles, apply Coulomb’s law to relate the magnitude of the electrostatic force, the charge magnitudes of the particles, and the separation between the particles.
  4. Identify that a shell of uniform charge attracts or repels a charged particle that is outside the shell as if all the shell’s charge were concentrated as a particle at the shell’s center.
  5. Identify that if a charged particle is located inside a shell of uniform charge, there is no net electrostatic force on the particle from the shell.
  6. Identify that the charge of a particle or object must be a positive or negative integer times the elementary charge.
  7. Identify that in any isolated physical process, the net charge cannot change (the net charge is always conserved).
  8. Identify an annihilation process of particles and a pair production of particles.

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charge-coulomb-law.pdf (0.89 MB )