Static Electricity Study Notes

Objectives - Static Electricity

• Key Terms: Static, electroscope, elementary charge, ground, grounding, conductors, insulators, coulomb, electric field, electric field intensity.

• Charging Mechanism: Friction causes objects to gain or lose electrons.

• Laws of Static Charges:

  • (a) Like charges repel

  • (b) Unlike charges attract

  • (c) Charges exert forces through distance.

• Atomic Structure Review:

  • Nucleus, electron cloud

  • Protons(+1), Neutrons, Electrons(-1)

  • Atoms are neutral.

• Electroscope Operation: Components include vanes or leaves, knob or plate.

• Law of Conservation of Charge: Movement of electrons conserved.

• Charging Methods:

  • (a) Friction

  • (b) Conduction

  • (c) Induction.

• Neutral Insulator Attraction: Neutral insulator can be attracted to a charged object (e.g., balloon to a wall).

• Coulomb Definition:

  • 1 Coulomb = _ electrons.

  • 1 electron = __ coulombs (exact number to be filled).

• Coulomb's Law:

  • Qualitative: Force (F) vs charge (q) and distance (d); inverse square law.

  • Quantitative: Solve problems; forces as vector quantities.

• Field Comparison: Electric field vs gravitational field.

• Electric Field Lines:

  • Point charge, oppositely/similarly charged points, oppositely charged parallel plates, charged rod.

  • Field lines drawn with a test positive charge, perpendicular to the surface.

• Electric Field Strength: Measured by E = F/q, units in newtons per coulomb; vector quantity.

• Conductor vs Insulator: Difference in ability to transfer charges (electrons).

• Grounding: Involves sharing electrons with the earth.