Electric charge and force

Electric charge and force

1. Combining electric force

   • 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

2. Electric force

   • Coulomb’s law describes the electric force
     • relates the strength of the electrostatic force between point charge to the magnitude of the charge and the distance between them .
   • The electric force acts along a line between the charges
     • the electric force acts along a the line connecting the two charges
   • The electric force keeps most objects close to neutral
   • The electric force is similar to the gravitational force

3. Electric charge

   • Rubbing objects together Can charge them
     • the effects of electric charge have been known since at least 600 B.C.
   • Atoms have positive, negative and neutral particles
     • through polarization, a charged rod can attract small objects that have zero total charge.
   • Electric charge is quantized
     • It states the fact that electric charge comes in integer multiples of e.
   • Electric charge can be transferred between objects
     • electric charge is conserved. This means that the total electric charge in the universe is constant.
   • Not all materials are good conductors
   • A Coulomb is a large amount of charge
     • it takes a lot of electrons to make 1 coulomb charge.
   • Charging by contact varies with the material
   • Electric charge comes in two distinct types
     • the positive and negative charge
   • An electric changer can attract a neutral object