Chpt 19 - Static Electricity Flashcards
What is Electrification by Contact?
When two different materials are rubbed together, they become electrically charged.
What is an insulator?
An object which does not allow electric charge to flow through it. (Eg. Plastic, rubber)
What is a conductor?
An object which allows electric charge to flow through it. (Eg. Metal)
Distribution of charge on an insulated conductor:
- All static charge resides on the outside of a conductor.
- Static charge on a conductor tends to accumulate where the conductor is most pointed.
What is Point Discharge?
The loss of charge from a point.
What is Coulomb’s Law?
States that the force of attraction or repulsion between two point charges is directly proportional to the product of the charges and inversely proportional to the square of the distance between them.
What is an Electric Field?
Any region of space where a static electric charge experiences a force other than the force of gravity.
What is an Electric Field Line?
A line drawn in an electric field showing the direction of the force on a positive charge placed in the field.
Name an Application of Electric Fields.
Photocopier.
Name an everyday effect of Static Electricity.
- Lightning
- Can cause explosions when there is fine particles in the air (eg. Flour in a flour mill)
Uses of a Gold Leaf Electroscope.
- Detects charge
- Indicates size of a charge
- Test whether an object is a conductor or insulator.
What is Electric Field Strength?
(At a point in an electric field) is the force per unit charge at that point. (Unit = Newton per Coulomb)
F = ( 1 / 4(Pi)ε )( QQ / d*2 )
Force = ( 1 / 4(Pi)ε ) ( Charge 1 x Charge 2 / distance*2 )
ε = ε(o)ε(r) permittivity
Permittivity = permittivity of vacuum x relative permittivity
