Electric Charges and Forces

Electric Charges and Forces

1. Electric Charge

   • Rubbing Objects Together can charge them
   • Electric Charge comes in two distinct types
     • Positive Charge
       • (+) for the charge on glass
     • Negative Charge
       • (-) for the charge on amber
     • Neutral Charge
       • Objects with zero total charge.
   • Atoms have positive, negative, and neutral particles
     • Electrons
       • Coulomb
     • Protons
     • Neutrons
   • Electric Charge is quantized
     • Charge quantization
   • A coulomb is a large amount of charge
   • Electric Charge can be transferred between objects
     • Ion
   • Charging by contact varies with the material
     • Triboelectric Charging
     • Charging by Collision
   • An electric Charge can attract a neutral object
     • The Polarization Process
   • Not all materials are good conductors
     • Insulators
     • Conductors
     • Free electrons
       • Semiconductors

2. Electric Force

   • Coulomb´s law describes the electric force
     • Coulomb´s Law
   • Electric Force acts along a line between the charges
   • Electric force is similar to gravitational force
     • Astronomical Systems
     • Atomic Systems
   • Electric forces keep most objects close to neutral

3. Combining Electric Forces

   • Electric Forces add by vector addition
   • Electric forces can be added graphically
   • A Spherical distribution of charge acts just like a point charge
     • Surface Charge Density