Static electricity


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Static electricity

  1. 1.  Understand the basic properties of electric charge. Differentiate between conductors and insulators. Distinguish between charging by contact, charging by induction, and charging by polarization.
  2. 2. Matter is made up of atoms. + Proton (positive charge) – neutron (neutral) + + + – electron (negative charge) – – atom nucleus
  3. 3. Electric charge is quantized.Charge is measured in coulombs (C).The fundamental unit of charge, e, is themagnitude of the charge of a singleelectron or proton. e = 1.602 176 x 10–19 C
  4. 4. An electrical conductor is a material in which charges can move freely.An electrical insulator is a material in which charges cannot move freely.
  5. 5. Relative +++++  Glasselectro-negativity  Human Hair ++++ranking for some  Nylon +++  Silkcommon materials ++  Furfrom electron donating +  Aluminummaterials (+, glass) to  Paperelectron accepting -  Cottonmaterials (-, teflon) --  Copper  Rubber ---  PVC ----  Teflon -----
  6. 6.  Insulators and conductors can be charged by contact. Conductors can be charged by induction. Induction is a process of charging a conductor by bringing it near another charged object and grounding the conductor.
  7. 7. A surface charge canbe induced oninsulators bypolarization.With polarization, thecharges withinindividual moleculesare realigned such thatthe molecule has aslight chargeseparation.
  8. 8. The electric force is proportional to the magnitude of each chargeand inversely proportional to the square of the distance between them.
  9. 9. Two balloons are charged with anidentical quantity and type ofcharge:-6.25 nC. They are held apart at aseparation distance of 61.7 cm.Determine the magnitude of theelectrical force of repulsion betweenthem.
  10. 10. Two balloons with charges of+3.37 µC and -8.21 µC attracteach other with a force of0.0626 Newton. Determinethe separation distancebetween the two balloons.
  11. 11. Joann has rubbed a balloon with wool togive it a charge of -1.0 x 10-6 C. She thenacquires a plastic golf tube with a chargeof +4.0 x 10-6 C localized at a givenposition. She holds the location ofcharge on the plastic golf tube a distanceof 50.0 cm above the balloon.Determine the electrical force ofattraction between the golf tube and theballoon.
  12. 12. At what distance of separationmust two 1.00-microCoulombcharges be positioned in orderfor the repulsive force betweenthem to be equivalent to theweight (on Earth) of a 1.00-kgmass?
  13. 13. A balloon with a charge of 4.0µC is held a distance of 0.70m from a second balloonhaving the same charge.Calculate the magnitude ofthe repulsive force.