### Lesson Objectives – the students should be able to:

- Explain how a simple battery can produce an electrical current.
- Define current, ampere, emf, voltage, resistance, resistivity, and temperature coefficient of resistance.
- Write the symbols used for electromotive force, electric current, resistance, resistivity, temperature coefficient of resistance and power and state the unit associated with each quantity.
- Distinguish between a) conventional current and electron current and b) direct current and alternating current.
- Know the symbols used to represent a source of emf, resistor, voltmeter, and ammeter and how to interpret a simple circuit diagram.
- Given the length, cross sectional area, resistivity, and temperature coefficient of resistance, determine a wire’s resistance at room temperature and some higher or lower temperature.
- Solve simple dc circuit problems using Ohm’s law.
- Use the equations for electric power to determine the power and energy dissipated in a resistor and calculate the cost of this energy to the consumer.
- Distinguish between the rms and peak values for current and voltage and apply these concepts in solving problems involving a simple ac circuit.
- Compute Power in Household Circuits
- Understand the Microscopic View of Electric Current
- Learn the concept of Superconductivity
- Could understand the Electrical Conduction in the Human Nervous System

### Lecture on Electric Currents PPT

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### Summary of Chapter 18

- A battery is a source of constant potential difference.
- Electric current is the rate of flow of electric charge.
- Conventional current is in the direction that positive charge would flow.
- Resistance is the ratio of voltage to current:
- Ohmic materials have constant resistance, independent of voltage.
- Resistance is determined by shape and material:
- ρ is the resistivity.
- Power in an electric circuit:
- Direct current is constant
- Alternating current varies sinusoidally
- The average (rms) current and voltage:
- Relation between drift speed and current:

### Units of Chapter 18 – Keywords

- The Electric Battery
- Electric Current
- Ohm’s Law: Resistance and Resistors
- Resistivity
- Electric Power
- Power in Household Circuits
- Alternating Current
- Microscopic View of Electric Current
- Superconductivity
- Electrical Conduction in the Human Nervous System
- Volta
- electrolyte

### List of Applied Physics / Physics 2 Lectures

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*credit: Giancoli Physics*

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