What day is it again?• The subatomic particle that has a positive charge

is called the ______________?

• The subatomic particle that is able to move to create a positive charge is called the _____________ ?

• A proton has a charge of ______Coulombs. One proton is (+/-) one fundamental or elementary charge. The # of Coulombs of one elementary charge is located on line __on the front of the Reference Table

Objectives• The fact that charge comes from protons and

electrons means that there must only be discrete amounts charge available to charged objects.

• Electrons are the only things that move, so even when something is positively charged we talk about an electron deficiency.

• Homework – Finish Worksheet/ Short C L• Test/Quiz Next Thursday !

• An object has three excess electrons.– What is its “elementary charge”?

– What is its charge in coulombs?

-3e

q = -3e x (1.6 x 10-19 C)/e = -4.8 x 10-19 C

Example #1

• An object has 75 protons and 65 electrons– What is its “elementary charge”?

– What is its charge in coulombs?

+10 e

q = +10e x (1.6 x 10-19 C)/e = +16 x 10-19 C

Example #2

Law of Conservation of Charge

• The total amount of charge in a closed system remains constant – charge is not created or destroyed, it only moves from one object to another

• Charge “moves” as a result of ELECTRON movement ONLY!!!

• A metal sphere with two excess electrons touches a neutral metal sphere and then taken away.

– What do you predict the charge on each sphere will be after they make contact?

– What is the total charge on both spheres after they come in contact?

-1e or -1.6 x 10-19 C

-2e or -3.2 x 10-19 C

The TOTAL CHARGE remains the SAME!!!

Example #3

End of 5.1.1 - PRACTICE