1. Electric Current and Ohm’s Law
Physical Science

2. Electric Current Types
Direct current – charge flows only in one direction.
Ex: battery operated items
Alternating current – a flow of electric charge that regularly reverses its direction.
Ex: plug into wall

3. Factors Affecting Conduction
Conductor – material through which charge can flow easily.
Resistance – opposition to flow of charge in a material.
resistance is affected by:
thickness (lowers)
length (increases)
temperature (increases)

4. Voltage
Voltage is a measure of potential difference – the difference in electrical potential energy between two places in an electric field.
Sources of voltage
battery (chemical energy)
solar cell (radiation energy)
generators

5. Units of Electricity and Ohm’s Law
Voltage = V Current = I Resistance = R V = I R

6. Homework
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Questions 1-8