This section deals with how a stationary charge is formed. ELECTROSTATICS This section deals with how a stationary charge is formed.

ELECTROSTATIC FORCES + + Similarly charged objects will repel each other. + + The larger the charge the greater the force of repulsion. + + Oppositely charged objects will attract each other. + -

Charging by Friction

Ebonite Rod: 4 protons and 4 electrons No charge Neutral Fur: 4 protons and 4 electrons No charge Neutral Initially both the ebonite rod and the fur are neutral, i.e they have equal numbers of protons and electrons.

This slide ONLY SHOWS the movement of electrons REMEMBER: Protons NEVER MOVE Only Electrons MOVE There are still 4 protons in each substance and 8 electrons in total As the two objects are rubbed together, enough energy by friction is generated to move some electrons around

Ebonite Rod: 4 protons and 5 electrons 1 more electron Negatively Charged Fur: 4 protons and 3 electrons 1 less electron Positively Charged Fur tends to lose its electrons easier than an ebonite rod, so ends up positive. The ebonite rod now has more electrons than protons and ends up with a net negative charge.

Insulators have no free electrons, so charge cannot flow through it. In order to create a static charge on an object, the charge must be unable to flow away. Insulators have no free electrons, so charge cannot flow through it. If charged by friction, only the area that was rubbed will become charged. Holding the other end with your hand will not discharge it, since the charge cannot flow to your hand.