Term 3 Week 8 2021

  Homework:

• Act 19A, p.219-220 Magnets
• Act 19B, p.223-225 Magnetic Forces
• Act 19C, p.228 Moving charges and Magnetism
• Act 20A, p.231-232 Intro to Electromagnetic Induction
• Act 20B, p.235-237 Electromagnetic Induction claculations




Magnetic Fields






Magnets 

Electromagnet

Electromagnet Used for Scrap Metal Crane



Levitating with Electromagnets


Exploding Cans with Electromagnets


Magnetic Fields




Right Hand Screw Rule





Right Hand Slap Rule



Right Hand Slap (Palm) Rule


Lorentz Force (F = Bqv)


Lorentz Force





Lorentz Force (F = BIL)










V = BvL

Note:
• emf is an old term for voltage and stands for electromotive force
• E is also used by enginers for Voltage (not energy)


D.C. Motor




D.C. Motor How it Works





Brushless D.C. Motor How it Works







Faraday Cage




Tesla Coil & Faraday Cage

Term 3 Week 5-7 2021

  Homework:

• Act 18A, p.201 Intro DC Electricity
• Act 18B, p.207 Simpler Equivalent Circuits
• Act 18C, p.209 Potential Dividers
• Act 18D, p.211-213 Using Ohm's Law

Current

Current is the rate of flow of Charge

I = Δq/Δt

Current

Voltage

Voltage (Potential Difference) is the change in energy (work done) to each coulomb of charge between two points on a circuit, or two points across an electric field

Circuit Symbols

Ohm's Law

Ohm's Law PhET application

D.C. Circuit Construction Kit PhET Application

D.C. Circuit Lab PhET Application

Ohm's Law

Series & Parallel Circuits

Series & Parallel Circuits

Electric Power

P = IV

P = I2R  ← using Ohm’s Law V=IR substitution

P = V2/R←using Ohm’s Law I=V/R substitution

D.C. Motor How it Works?

Week 3 Term 3 2021

 Homework:

• Act 17A, p.192-194, Electric Fields

PhET - Charge & Electric Fields - App

Basics of Electric Charge

Definition of an Electric Field:

“Any region of space where a charge feels a force.”

A positive charge will feel a force with the electric field direction

A negative charge will feel a force against the electric field direction

Fe = Eq

Electric Field

Electric Potential (Voltage)

What is Voltage?

Uniform Electric Field

E = V/d

Uniform Electric Fields

Uniform Electric Field

E = V/d

E: Electric Field (Vm-1 or NC-1 depending on the context

used)

Electric Force

Fe = Eq

Fe: Electrical Force (N)

q or Q: Charge (C)

Electrical Potential Energy

As the charge falls through the Electric Field, the electrical potential energy transforms into kinetic energy.

Ek = Ep

½ mv2 = Vq

Electron Gun

(Cathode Ray Tube)

A Tube Screen TV is an Electron Gun

Cathode Ray Tube and how it works

Electron Gun

Cathode Ray Tube (CRT)

Discovery of the Electron: Cathode Ray Tube Experiment

Cathode Rays Leads to Thomson's Model of the Atom

Parker Solar Probe - Use of CRT

Millikan's Oil Drop Experiment

Charge of an Electron - Millikan's Oil Drop Experiment

Week 8 Term 2 2021

Week 9 Term 2 2021 

Homework

• Act 5A, p,53-54, Pulses and Waves
• Worksheet on Superposition and Reflection
• Act 5B, p. 58, Reflection, Refraction and Diffraction of Waves
• Act 5C, p.63-64, Diffraction and Superposition
• Act 6A, p.69, Plane Mirrors
• Act 6B, p.76-77, Curved Mirrors
• Act 7D p.89-90, Lenses

Lens/Mirror Simbucket - app link

Plane & Curved Mirrors

Lenses

Ray Diagram

Comparing Lens & Mirror

Using Descartes formula for the Lens & Mirror

Term 2 Week 7 2021

 

• Act 15A, p. 173-176, Particles and Half-Life
• Act 16A, p. 181, Nuclear Reactions
• Act 5A, p,53-54, Pulses and Waves
• Worksheet on Superposition and Reflection
• Act 5B, p. 58, Reflection, Refraction and Diffraction of Waves
• Act 5C, p.63-64, Diffraction and Superposition
• Act 6A, p.69< Plane Mirrors

Diffraction

• The Bending of Waves Around Corners
• Larger Wavelength, 𝛌 - greater the angle of diffraction
• Shorter Wavelength, 𝛌 - smaller the angle of diffraction
• Also the smaller the gap the greater the angle of diffraction

Diffraction

Diffraction of Water Waves in a Ripple Tank

Reflection on A String

Hard Boundary

Wave reflects on opposite side (opposite phase)

Same Amplitude, A

Same Wavelength, 𝛌

Same Wave Speed, v

Reflection on A String

Soft Boundary

Wave reflects on same side (same phase)

Same Amplitude, A

Same Wavelength, 𝛌

Same Wave Speed, v

Refraction on A String

Fast to Slow Boundary

Relation of waves to Incident Wave

Reflected Wave - same speed - same wavelength 𝛌 - opposite phase

Refracted Wave - slower speed - smaller wavelength 𝛌 - same phase

Refraction on A String

Slow to Fast Boundary

Relation of waves to Incident Wave

Reflected Wave - same speed - same wavelength 𝛌 - same phase

Refracted Wave - faster speed - larger wavelength 𝛌 - same phase

Cymatics

Cymatics

Cymatics: Hose Pipe Water Experiment

Singing plates - Standing Waves on Chladni plates

Cymatics: Ruben's Tube Vs. Tesla Coil

Sound + Fire = Rubens' Tube

A better description of resonance

Snell's Law & Critical Angle

The Critical Angle occurs when a wave is attempting to pass from a medium with a slower speed to that of a higher speed 

low v → higher v

low 𝜆 → higher 𝜆

high n → lower n

The Critical angle is the incident angle where the refracted angle equals 90 degrees

Refraction Bending Light PhET Application

Snell's Law

• Any incident above the Critical angle will prevent any refraction occuring and Total Internal Reflection will occur
• The Critical angle is can be found by sin(𝜭c) = n2/n1

FibreOptic Cables: How they work?

Total Internal Reflection T.I.R.

What Happens to Lazers Underwater?