Electric Forces

• According to the Law of Electric charges, like charges repel & unlike charges attract.
• The region surrounding a charged object is called an electric field. The attractive or repulsive force between charged objects is called the electric force.
• The strength of the electric force between charged objects depends on

  • the size of the charges of each object
  • the distance between the objects
• The greater the charges and the closer together they are, the greater the electric force between them.
• Electrons travelling from one atom to another atom is an electric current.
• An outside force causes one or more valence electrons of an atom to get 'bumped' from one atom to an adjacent atom, which in turn forces that atom to give up one or more electrons to the next atom. This becomes a chain affect that continues, which is an electric current.
• The electrons of copper and other metallic atoms are only loosely attached, which allows electrons to travel through these materials easily. These materials are called conductors.
• Materials through which electrons do not move easily are called insulators. Glass, rubber, wood, plastic and even air are good insulators.
• In a home, copper wires allow electrons to flow easily to power electric devices. Plastic and rubber are used as protective electric insulators around the metal wire.
• Static charge is a buildup of positive or negative electric charge on an object. This happens because some materials hold electrons more loosley than others.
• Static discharge is when electrons build up on a surface and then suddenly discharge.
• When you touch a door handle after walking on carpet, there is a buildup of electrons in your hand that jump to the doorknob and cause a small electric shock.
• A dramatic example of static discharge is lightning, which is a giant spark caused when negative charges from a cloud jump to the positive charges on the ground/another cloud.