Resistivity, Ohms Law and Resistance in Series and Parallel

Resistivity, Ohms Law and Circuit Construction

John Rudolf D. Catalan

Special Science Teacher I

Engage

Poll

Which of the following illustrations can conduct electricity?

Poll

What do you think the characteristics of a conductor?

• Composed of Plastic

• Malleable

• Metallic in Nature

• Composed of Electrons, Protons and Ions

• Ductile

Recall

That a conductor is any material that can conduct (transfer electron) from one place to another.

Multiple Choice

What do you call the movement of electron across the potential differences of a particular source (battery)

• Resistance

• Capacitance

• Voltage

• Current

KE (Increase) = Velocity? , Stored Energy?

PE (Increase) = Velocity? , Stored Energy?

Explore

Open Ended

When you think about the word "resistance", what comes to your mind if you recall that word?

Resistance is a measure of the opposition to current flow in an electrical circuit. Resistance is measured in ohms, symbolized by the Greek letter omega (Ω)

Open Ended

So..... If we apply more resistance to the wire, what will happen to the flow of energy ?

Explain

Voltage will be the distance of the tube in order to flow water from one place to another (due to gravity)

Current will be the strength of water flow based on the characteristics of the tube (diameter, size , structure)

Resistance will act as a "gauge" that will limit the flow of water

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Sample Problems

• Compute the resistance of the certain material (iron) that is 15 m length and 4.5 cm in diameter (resistivity of the iron : 1.0 x 10^-7 Ω/m

• An electrician wishes to cut a copper wire (ρ=1.72 x 10^-8Ω/m)that has no more than 10Ω of resistance. The wire has a radius of 0.725mm. Approximately what length of wire has a resistance equal to the maximum 10Ω ?

  
  

Resistance in Series and Parallel

Activity

Series and Parallel Connection Construction