Lesson-1.1-ELECTRIC-CHARGE

Page 1: Course Overview

• Institution: Hilongos National Vocational School

• Subject Title: General Physics 2 (Electricity and Magnetism)

• Instructor: Allen I. Dalinog

• Academic Year: 2024-2025

Page 2: Subject Description

• Class Description:

  • Focus on electricity, magnetism, optics, basics of special relativity, atomic and nuclear phenomena.

  • Utilizes algebra, geometry, trigonometry, graphical analysis, and basic calculus.

• Class Schedule: MWF (Monday, Wednesday, Friday)

• Class Duration: 1 hour and 20 minutes

Page 3: Grading System

• Written Works: 25%

• Performance Tasks: 45%

• Mastery and Quarterly Exam: 30%

• Course Requirements:

  • Scientific Calculator

  • Physics Notes

  • Completed Activities

  • Concept Map Making

  • Attendance

Page 4: Unit 1 Introduction

• Lesson:

  • Electricity and Magnetism

  • Instructor: Allen I. Dalinog

  • Year: 2024-2023

  • University Affiliation: University of Cebu - Main Campus SHS Department

Page 5: Lesson Objectives

1. Discuss the concept of electric charge with reference to subatomic particles.

2. Describe charging by rubbing and induction using diagrams.

3. Explain the role of electron transfer in electrostatic charging by rubbing.

Page 6: Concept Engagement

• Question Posed:

  • What do you think happened?

Page 7: Definitions

• Electricity:

  • A form of energy involving the movement of electrons from one point to another.

• Electrostatics:

  • Study of phenomena associated with charged bodies at rest.

Page 8: Historical Context

• Sir William Gilbert:

  • Coined the term "Electricity" derived from the Greek word "elektron" (amber).

  • Discovered law of attraction and repulsion between magnets.

Page 9: Benjamin Franklin

• Credited for linking electricity with lightning through his famous Kite Experiment.

Page 10: Key Figures in Electricity

• Contributors:

  • Alessandro Volta

  • André-Marie Ampère

  • Charles Augustin de Coulomb

  • George Ohm

  • Graham Bell

  • Thomas Edison

  • James Maxwell

  • Michael Faraday

Page 11: Influential Scientists

• Notable Figures:

  • Nicola Tesla

  • Albert Einstein

Page 12: Static Electricity

• Definition:

  • The buildup of electrical charges on an object.

  • Occurs through electron transfer from one object to another.

Page 13: Electric Discharge

• Definition:

  • Loss of static electricity as charges move off an object.

• Types of Discharge:

  • Within Cloud: Charge transfer between negative base and positive top (intra-cloud).

  • Cloud-to-Cloud: Discharge between charge centers in clouds.

  • Typical Cloud-to-Ground Lightning: Discharge between ground and negative charge centers.

Page 14: Particles and Charge

• Subatomic Particles:

  • Mass and Charge:

    • Protons: Mass present, Positive Charge (+)

    • Neutrons: Mass present, No Charge

    • Electrons: Negligible mass, Negative Charge (-)

• Charge:

  • Charge symbol: q

  • SI Unit: Coulomb (C)

Page 15: Quantization of Charge

• Example 1:

  • To have a charge of 1.0 C, how many electrons must be removed?

• Example 2:

  • Rubbing a comb on hair gives a comb charge of -0.96 C: (a) Identify which material loses and gains electrons.(b) Calculate the number of electrons transferred.

• Concept:

  • Charge is quantized; it must be integral multiples of the fundamental charge (e).

  • 1 C = 6.242 x 10^18 electrons.

Page 16: Charging Mechanisms

• Positive Charge:

  • Object becomes positively charged if it loses electrons.

• Neutrality:

  • All objects start neutral and may become either positively or negatively charged.

• Negative Charge:

  • Object becomes negatively charged if it gains electrons.

Page 17: Laws of Electric Charge

• Law of Electric Charge:

  • Like charges repel; unlike charges attract.

• Law of Conservation of Charge:

  • Charges cannot be created or destroyed.

Page 18: Methods of Charging Objects

• Ways to Charge:

  • Conduction

  • Friction

  • Induction

Page 19: Charging by Friction

• Definition:

  • Rubbing two objects causes electrons to transfer ("wiped").

  • Leads to electrostatic discharge.

Page 20: Triboelectric Series

• Definition:

  • List of materials ranked by their tendency to gain or lose electrons.

• Conductors vs Insulators:

  • Top items lose electrons (positive); bottom items gain electrons (negative).

Page 21: Example of Triboelectric Effect

• Example:

  • Rubbing dry hands with silk:

  • Dry hands lose electrons (positively charged).

  • Silk gains electrons (negatively charged).

Page 22: Charging by Conduction

• Definition:

  • Transfer of electrons through direct contact.

• Example:

  • Negatively charged cylindrical rod touches a neutral spherical conductor, charging it by conduction.

Page 23: Electroscope

• Function:

  • Determines if an object is electrically charged.

• Components:

  • Knob, metal rod, metal leaves within a flask.

• Indications:

  • Charged objects cause leaves to repel.

Page 24: Charging by Induction

• Definition:

  • Rearrangement of charges in an uncharged object without direct contact with a charged object.

Page 25: Polarization

• Definition:

  • Process by which a neutral body becomes polarized through molecular rearrangement.

• Concept of Electric Dipole:

  • A body with a positive charge on one end and a negative charge on the other (dipole).

Page 26: Practical Observation

• Observation:

  • Cords coming from walls made with plastics and metals (insulators and conductors).

Page 27: Conductors and Insulators

• Conductors:

  • Allow easy flow of charge

  • Examples: Silver, copper, gold, aluminum

• Insulators:

  • Do not allow flow of electrons

  • Examples: Plastic, rubber, glass, wood, air

• Semi-conductors:

  • Conduct better than insulators but not as well as conductors

  • Examples: Silicon, germanium

Page 28: Knowledge Check Questions

• Question:

  • An object becomes positively charged when which occurs?

  • A. Loses electrons

  • B. Gains electrons

  • C. Loses protons

  • D. Gains neutrons

• Question:

  • If two charges repel each other, they must be:

  • E. Positive and neutral

  • F. Positive and negative

  • G. Negative and negative

  • H. Neutral

Page 29: Conceptual Understanding Check

• Question:

  • Which can be attracted by a positively charged object?

  • A. Another positively charged object

  • B. Any object

  • C. A neutral object

  • D. No other object

• Scenario:

  • Two rubbed balloons nearing each other; result?

  • E. Repel each other

  • F. Attract each other

  • G. Both become positively charged

  • H. They pop.

Page 30: Applied Concepts Check

• Question:

  • Using a charged spoon to pick up salt and pepper is an example of charging by:

  • A. Induction

  • B. Conduction

  • C. Friction

  • D. Static discharge

• Question:

  • Best definition for polarization?

  • E. Two objects attraction due to charge

  • F. Neutral object's charges jump to a charged surface due to opposite attraction

  • G. Neutral object's charges separate due to nearby charge

  • H. Object gains charge from another object.

Page 31: Induction and Friction Basics

• Inquiry:

  • A charged balloon brought near an electroscope without touching demonstrates:

  • A. Convection

  • B. Friction

  • C. Conduction

  • D. Induction

• Example of Friction:

  • Rubbing a balloon in your hair is an example of charging by:

  • E. Induction

  • F. Conduction

  • G. Friction

  • H. Grounding

Page 32: Advanced Concept Questions

• Scenario:

  • A positively charged rod near a neutral metallic plate induces:

  • A. Positive charge

  • B. Negative charge

  • C. Neutral charge

  • D. Depending on distance

• Question:

  • A neutral electroscope touched with a negatively charged rod results in:

  • E. Positive charge

  • F. Negative charge

  • G. Remains neutral

  • H. It depends on contact time.