Electrical Charge

1
Electrical Charge
2
Measurements

• The Electroscopes
• Pith ball
• Metal foil
• Large metal foil

3
Materials

• Conductors
• Electrons move readily with a charge
• Insulators
• Electrons movement is greatly reduced
• Semi-Conductors
• Electron flow are controlled by
• holes (p type) or free (n type) electrons

4
Types of Charges

• Name the four conditions of electrical charge
• Neutral the number of negative and positive
  charges are equal
• Negative the number of electrons exceed the
  number of protons
• Positive Charge the number of electrons is less
  than the number of protons
• Ground neutral condition because of the number
  of charges available. The Earth is a ground
  for all types of charge.

5
Conduction of Charge
6
Conduction

• When negatively charged electroscope is touched
  by a hand ... Describe the exchange of charge.
• Electrons are repelled by the same charge
• The hand (ground) removes electrons by
  conduction.
• As the hand is removed, the neutral charge is
  uniformly distributed
• The hand and electroscope have same neutral
  charge (conduction)

7
Charge by Conduction and Induction
8
Charging by Conduction and Induction

• When negatively charged balloon is brought near
  electroscope, Describe the change in charges.
• Electrons are repelled by the same charge
• The leaves repel each other with the same charge
  (conduction)
• The hand (ground) removes electrons by
  conduction.
• As the balloon is removed, the positive charge
  uniformly distributed
• The balloon and electroscope have opposite
  charges after the induction

9
2 Charging Two Spheres
10
Charging by Conduction and Induction 3

• Suppose a negatively charged balloon is brought
  close to one of the two identical insulated metal
  spheres. Describe the change in charge.
• Electrons from the first sphere will be pushed
  onto the sphere farther from the balloon
  ......What charge will each sphere get?
• the first sphere positively charged
• the second sphere negatively charged
• If the spheres are then separated, how does the
  charge change?
• Both will receive an equal but opposite charge.

11
Summary

• There are four charged conditions Negative,
  Positive, Neutral, and Ground
• Conduction distributes the same charge to all
  objects.
• Induction will leave an opposite charge.
• Induction can charge objects through use of a
  ground.