Electricity and Magnetism:

1
Electricity and Magnetism
2
Review Kinetic Energy

• Car
• 2000 kg and 30 m/s
• Truck
• 50,000 kg and 30 m/s
• Space Shuttle
• 2,000,000 kg and 6900 m/s

3
Review Kinetic Energy

• Car
• 2000 kg and 30 m/s
• 2000 x 30 x 30 / 2 900,000 J 900 kJ
• Truck
• 50,000 kg and 30 m/s 45 MJ
• Space Shuttle
• 2,000,000 kg and 6900 m/s 4.8x107 MJ

4
Atomic Bomb / Cloud Chamber

• Cloud chamber detects atomic and subatomic
  particles and photons
• Physicists could see the interior of atom with
  tools like these (still in use today)
• Nuclear structure was discovered and led to
  fission

5
Electric and Magnetic Forces

• Same force, different forms
• Maxwell equations (1880s)
• Similar to Newtonian mechanics
• Speed of light
• Basics
• Positive and Negative charges
• Force proportional to charges and 1/r2

6
Magnetism

• No monopoles yet
• We talk about N and S poles
• Moving charges generates magnetic field
• Superconductivity gives big magnets
• Magnets affect motion of charged particles
• Cloud chamber again

7
Magnetic Field of Earth

• Earth has primarily Iron inner core
• Moving liquid ionic mantle/outer core

8
Northern Lights

• Byproduct of Magnetic Field

9
Electricity What is it?

• Moving electrons in wires
• What moves them?
• Electrical potential energy
• Batteries and other power sources

10
DC and AC Motors

• Combine magnets and electricity

11
Light

• Oscillating electric field
• Matching oscillating magnetic field
• Frequency range varies widely
• Speed of waves are constant

12
Interaction of Light with Matter

• Microwave oven (water rotation)
• IR heat lamps (warm food)
• Radio waves (communication)
• Visible (sight)
• X-rays (medical)