Physics 242

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Physics 242 Electric Charges
Types and Sources of Electric Charge
Two kinds of electric charge positive
negative
protons
electrons
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Physics 242 Electric Charges
Types and Sources of Electric Charge
THANKS BEN!
Ben Franklin actually did a great deal of
experimentation in the area of electricity.
However, Ben Franklin chose the wrong sign
convention for charge it has stuck ever since.
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Physics 242 Electric Charges
Properties of Electric Charge

• Charge is quantized.
• Positive and Negative charges have same
  magnitude
• e p 1.6 x 10-19 C
• SI unit of charge is the Coulomb
• Charge is conserved.

http//www-personal.umich.edu/jcv/imb/imb.html
http//www.wikipedia.org/wiki/Proton_decay
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Physics 242 Electric Charges
Atoms and Materials
Classification of Materials Conductors,
Insulators, Semiconductors
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Physics 242 Electric Charges
How do we charge an object? A. Tribocharging -
Charging by rubbing
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Physics 242 Electric Charges
How do we charge an object? A. Tribocharging -
Charging by rubbing
Conductors charge will distribute around the
surface to try until equilibrium is
achieved. - charge only resides on
surface, not inside.
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Physics 242 Electric Charges
How do we charge an object? B. Induction
Inducing a charge without touching.
Conductors
Charge is physically moved in/on the materials.
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Physics 242 Electric Charges
Conductors An Example
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Physics 242 Electric Charges
How do we charge an object? B. Induction
Inducing a charge without touching.
Insulators