Coulomb's Law

• Static Electricity
• known since ancient times
• examples
• hair standing on end
• "sparking"
• balloon on wall
• Observations
• Glass and Rubber rods
• rubber rod and fur
• glass rod and silk
• Two possibilities
• repel
• the two rubber rods or the two glass rods (Requires RealPlayer)
• attract
• rubber rod and glass (Requires RealPlayer)
• Explanation
• "positive" and "negative"
• convention and the flow of charge
• from an electrical p.o.v.
• (-) to left is equivalent to (+) to right
• charge
• inherent physical property of subatomic particles
• protons and electrons
• Electrical Charge
• Fundamental Quantity
• measured in Coulombs [C]
• not continuous distribution
• New Conservation Law
• Charge is conserved!
• Charges exert forces.
• How to Charge
• By Friction
• By Induction
• redistribute
• ground
• remove ground
• redistribute
• See Simulation
• Classification of Materials
• Conductors
• charges move freely
• Insulators
• charges do not move freely
• Semiconductors



• Coulomb's Law
• Electrical Force
• depends on size of charges (q₁ q₂)
• depends on separation (1/r²)
• attractive - opposite charges
• repulsive - like charges
• Coulomb's Law Simulation
• Coulomb's Law

• Examples