Term 3 Week 7 2018

Homework:

• Ex 6A, p.188-196 Electric Fields
• Ex 6B, p. 200-201 I = Q/t
• Ex 6C, p. 205-214 D.C. Circuits

Transistors - The Invention that Changed the World

Term 3 Week 6 2018

Homework:

• Ex 6A, p.188-196 Electric Fields

Electron Gun

Cathode Ray Tube (CRT)

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

Term 3 Week 5 2018

Homework:

• Ex 6A, p.188-196 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

Term 3 Week 4 2018

Homework

• Ex 3D, p.66--67, Wave Properties
• Ex 3E, p.69-70, Diffration
• Ex 3F, p.73-75 Superposition
• Ex 3G, p.76-78 Two Point Source Interference
• Ex 3H, p.81-83 Waves on a String
• Ex 3I, p.85-87 Wave Refraction on a String
• Ex 3B, p.47-52, Refraction
• Ex 3C, p.56-63, Lens
• Ex 3A, p.37-44 Curved Mirror

Plane & Curved Mirrors

Lenses

Ray Diagram

Comparing Lens & Mirror

Using Descartes formula for the Lens & Mirror

Term 3 Week 3 2018

Homework

• Ex 3D, p.66--67, Wave Properties
• Ex 3E, p.69-70, Diffration
• Ex 3F, p.73-75 Superposition
• Ex 3G, p.76-78 Two Point Source Interference
• Ex 3H, p.81-83 Waves on a String
• Ex 3I, p.85-87 Wave Refraction on a String
• Ex 3B, p.47-52, Refraction
• Ex 3C, p.56-63, Lens
• Ex 3A, p.37-44 Curved Mirror

Lens

Simbucket Lens/Mirror Lab - App

GeoGebra Lens - App

GeoGebra Mirror App

Lens Concave & Convex

Term 3 Week 2 2018

Homework

• Ex 3D, p.66--67, Wave Properties
• Ex 3E, p.69-70, Diffration
• Ex 3F, p.73-75 Superposition
• Ex 3G, p.76-78 Two Point Source Interference
• Ex 3H, p.81-83 Waves on a String
• Ex 3I, p.85-87 Wave Refraction on a String
• Ex 3B, p. 47-52, Refraction

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

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?

Term 3 Week 1 2018

Homework

• Ex 3D, p.66--67, Wave Properties
• Ex 3E, p.69-70, Diffration
• Ex 3F, p.73-75 Superposition
• Ex 3G, p.76-78 Two Point Source Interference
• Ex 3H, p.81-83 Waves on a String
• Ex 3I, p.85-87 Wave Refraction on a String
• Ex 3B, p. 47-52, Refraction

Refraction

v1/v2 = 𝛌1/𝛌2 = sin(𝜭1)/sin(𝜭2) = n2/n1

Wave Refraction

n1sin(𝜭1) = n2sin(𝜭2)

Snell's Law (for Light Only)

PhET Refraction application

Apparent position of an object underwater

Refraction of Waves

Snell's Law

v1/v2 = 𝛌1/𝛌2 = sin(𝜭1)/sin(𝜭2) = n2/n1 ← Wave Refraction

n1sin(𝜭1) = n2sin(𝜭2) ← Snell’s Law (light only)

Term 2 Week 10 2018

Homework

• Ex 3D, p.66--67, Wave Properties
• Ex 3E, p.69-70, Diffration
• Ex 3F, p.73-75 Superposition
• Ex 3G, p.76-78 Two Point Source Interference
• Ex 3H, p.81-83 Waves on a String
• Ex 3I, p.85-87 Wave Refraction on a String

PhET Waves on a String App - link

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

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

Two Point Source Interference

Two Point Source Interference

Double Slit Experiment

PhET Sound Wave Interference - link

PhET Wave Interference - link

Cymatics

Term 2 Week 9 2018

Homework

• Ex 3D, p.66--67, Wave Properties
• Ex 3E, p.69-70, Diffration
• Ex 3F, p.3F, p.73-75 Superposition

Basic Properties of Waves

waves transfer energy through a medium without transferring the medium itself

• Cycle - a basic repeating unit in a wave
• Amplitude A (m) - the distance from the middle point to the top of a crest, or bottom of a trough
• Wavelength 𝜆 (m) - the distance/length of one cycle
• Period T (s = s per cycle) - the time it takes for one cycle to pass a point
• Frequency f (Hz = cycles per second) - the number of cycles that pass in one second

T = 1/f & f = 1/T

• Wave Speed v (ms-1) the speed of a wave

v = 𝜆/T & v = f𝜆

Wave Properties

Frequency & Period

Wave Phase

Pendulum Waves

Longitudinal Waves

particle displacement in the medium is parallel to the direction of wave propagation e.g. sound waves, primary earthquake waves

Transverse Waves

particle displacement in the medium is perpendicular to the direction of wave propagation e.g. light and other electromagnetic waves, secondary earthquake waves

• Superposition of Waves: two waves traveling through each other will not change each other motion in any way, but they will add to one another when they overlap
• Constructive Interference - Reinforcement - In Phase
• Deconstructive Interference - Cancellation - Out of Phase