Lecture Notes on Charged Particles and Electromagnetism

Properties of Charged Particles

• Charges: Particles can have a positive or negative charge.
• Interactions:
  • Same charge: repel each other
  • Opposite charges: attract each other

Electric Fields and Voltage

• Electric Fields: Created by charged particles; exert force on other charged particles.
• Voltage:
  • Defined as the energy between two points in an electric field.
  • Analogy: Height of a mountain represents voltage.
    • Higher elevation = more energy (damage potential).
• Power:
  • Total Power = Voltage × Current
  • Current is the number of charged particles flowing.

Circuits and Current

• Flow of Charged Particles:
  • In a circuit, charged particles flow through wires.
  • If the wire is cut, current stops.
• Battery Function:
  • Creates electric field pushing charged particles along.
  • Does not create charged particles; just facilitates their movement.
• Light Bulb Examples:
  • If one bulb breaks, all lights turn off in a series circuit.
  • In a parallel circuit, other lights stay on.
• Increasing Voltage:
  • More batteries = more voltage = brighter lights.

Magnetic Fields and Motion

• Magnetic Fields: Created by moving charged particles.
• Magnetic Poles:
  • A magnet has a North Pole and a South Pole.
• Magnetic Field Interaction: Exerts force on other moving charged particles.
• Spinning Charges:
  • Charged particles moving in loops create magnetic fields.
• Current and Magnetism:
  • Current through a wire creates a magnetic field.
  • Reversing current reverses magnetic field direction.

Electric Motors

• Functionality:
  • Changing current direction causes magnet rotation.
  • Basis for electric motors.

Electromagnetic Interaction

• Changing Fields:
  • Moving magnets create changing magnetic fields, which in turn create electric fields.
  • Must keep moving to maintain this effect.
• Power Generation:
  • Power plants use rotating magnets to generate electricity.

AC vs. DC Current

• AC (Alternating Current):
  • Voltage and current alternate direction.
• DC (Direct Current):
  • Voltage and current remain in the same direction.

Electromagnetic Waves

• Generation:
  • Changing magnetic fields create electric fields and vice versa, causing a chain reaction.
• Communication:
  • This phenomenon allows radios and cell phones to communicate.
• Visible Light:
  • A form of electromagnetic wave with higher frequency than radio waves.
• Other Electromagnetic Waves:
  • X-rays and gamma rays have even higher frequencies.