Tuesday  January 12 1999
Announcements: The syllabus was handed out.

Lecture notes:
 

1. The Four Fundamental Forces

1. Strong Force
2. Weak Force
3. Gravity: covered in Phys 201
4. Electromagnetic Force: covered in 202

1. What we’ll learn in 202

1. Four Fundamental laws about electromagnetism

1. Maxwell’s equations

1. Electricity and Magnetism are the basis for many phenomena

1. Electricity- lightning current
2. Radiation- light x-rays
3. Magnetism- electric motors MRI
4. Chemistry- chemical bonds reactions

1. Electric Charges
2. Current
3. Magnetic Fields

1. Electric Charge

1. Two types of charges: Positive and Negative

1. Like charges repel

1. Opposite charges attract

1. Atomic Structure

1. a negative electron cloud
2. nucleus of protons and uncharged neutrons

1. All objects tend to contain equal amounts of negative and positive charges and stay electrically neutral.
2. It is possible for an object to pick up an extra positive or negative charge. The object will have the either a positive or negative charge depending on the extra charges
3. Charges are measured in units of Coulomb (C)

1. A Coulomb is the amount of charge flow through the cross section of a wire in 1 second when there is a current of 1 ampere ( Amperes will be discussed in a later chapter)
2. The amount of charge carried by an electron is 1.6x 10¹⁹ C

1. Electrons move differently in different materials

1. Insulators- electrons move slowly

Ex. Wood plastic

2. Conductors- electrons move quickly

Ex. Metals

3. Semiconductors- intermediate electron motion can be manipulated

1. Coulomb’s law

1. Like charges repel
2. Opposite charges attract