University

Physics 2

Physics 2

Fall 2024

The following are items of interest from the news and other media, relavant to the class content. They are organized by textbook chapter.

- Ch 5: Electric Charges and Fields
- Ch 6: Gauss’s Law
- Ch 7: Electric Potential
- Ch 8: Capacitance
- Ch 9: Current and Resistance
- Ch 10: DC Circuits
- Ch 11: Magnetic Forces and Fields
- Ch 12: Sources of Magnetic Fields
- Ch 13: Electromagnetic Induction
- Ch 14: Inductance
- Ch 15: Alternating-Current Circuits
- Ch 16: Electromagnetic Waves
- (Vol 3) Ch 1: The Nature of Light
- (Vol 3) Ch 2: Geometric Optics and Image Formation
- (Vol 3) Ch 3: Interference
- (Vol 3) Ch 4: Diffraction
- General Topics
- Playing Shockwave Flash

See also: Resources Page

- Videos:
- Fiery Looping Rain on the Sun (4 min)

- Lecture videos
- Microscopic Charges (6:39) – Ions (4:21) – The Teflon Rod - Charge (4:56) – Triboelectricity (5:45) – Force Magnitude (5:49) – Feynman’s Example (6:32) – Force Vector (5:33) – Fields & Forces 1 - What is a Field? (4:13) – Fields & Forces 2 - Definition (6:32) – Fields & Forces 3 - Point Charge (6:53) – Continuous Charge Model (5:10) – Differential Element (5:33) – Charged Rod Solution (8:34) – Charged Rod Problem 1 (9:22) – Charged Rod Problem 2 (8:04) – Saved by Symmetry (7:57) – Forces and Kinematics (7:08) – Field Lines (5:50) – Lines Around Point Charges (6:08) – 2D & 3D Charge (10:18) – Field of a Charged Disk pt. 1 (8:18) – Field of a Charged Disk pt. 2 (5:53)

- Example problem videos – Adding Forces I (7:22) – Adding Forces II (3:58) – Use That Unit Vector! (8:31)
- Simulations & Interactive Figures
- PhET sims – Electric Field Hockey – Charges and Fields – Balloons and Static Electricity – Electric Field of Dreams
- electroscope sim
- vector field vizualization java applet
- Electric field line simulator
- PhysicsClassroom.com interactives
- interactive figures (swf) – electric force and field (swf) – Coulomb force (swf)

- Lecture videos
- Flux: The Concept of Vector Flux (3:16) – The Mathematics of Vector Flux (2:59) – Vector Flux Examples (3:44) – Vector Flux of a Curved Surface (3:53)
- Gauss’s Law: Statement of Gauss’s Law (3:31) – Gauss’s Law Examples (9:31) – Gauss’s Law for a Point Charge (9:06) – Gauss’s Law for a Line Charge (14:36) – Gauss’s Law for a Charged Plane (11:54) – Gauss’s Law for a Charged Sphere (10:56)
- Conductors – Field Inside a Conductor (8:39) – Field Outside a Conductor (4:39) – Field at a Conductor Surface (5:50) – Electrostatic Shielding (4:14) – Electrostatic Shielding Demo (3:47)

- Example Problem Videos – Problem 24-19 (4:14) – Problem 24-23 (7:08) – Problem 24-27 (5:27) – Problem 24-37 (1:53) – Problem 24-53 (3:04) – Problem 24-54 (2:01) – Problem 24-60 (5:21)
- videos:
- Demo: Corona discharge spins the Electrostatic Windmill (3:43)

- Lecture videos
- Potential Energy Reminder (5:09) – A Mechanical/Electrical Analogy (4:30) – Definition of Electric Potential (3:48) – Potential of a Point Charge, Away (5:47) – Potential of a Point Charge, Toward (4:15) – Compare the Paths (2:08) – From Potential Energy to just plain Potential (1:26) – Potential of a Point Charge Set Up (4:26) – Potential of a Point Charge Solution (1:45) – eV - A Microscopic Unit for Energy (4:06)

- Example problem videos – Energy of Charge Assembly (11:16) – Energy of charges on cube (6:40) – Energy and Kinematics of Charges (6:19)
- videos:
- Why Lightbulbs Might Be The Best Invention Ever (19 min) explains how the “electron gun” inspired invention of the vaccuum-tube transistor, which form the basis of computer operation

- PhET Simulations – Capacitor Lab – John Travoltage
- videos:
- capacitor as defibrillator
- high voltage power line inspection – man in a faraday-cage suit
- super capacitors as next-generation batteries
- dielectric breakdown (9 sec) of air at a power plant

- Lecture videos
- Defining the Capcaitor (6:27) – Parallel Plate Capacitance (10:45) – Field in a Capacitor (8:17) – Capacitor Energy (4:58) – Capacitor with a Dielectric (4:33) – Dielectric Demonstration (8:13)

- Example problem videos – Capacitor network 1 (7:23) – Capacitor network 2 (8:21) – Capacitor network 3 (3:55)

- simulations – Phet Circuit Construction Kit
- videos of superconductor tricks
- Meissner Effect (6.5 min)
- Superconducting Levitation (2 min)

- Lecture videos
- Why Charges Move (4:26) – Simple Definition (3:53) – Charge Carriers (3:34) – Microscopic Model (6:04) – Defining the Battery (6:06) – Ohms “Law” Statement (4:01) – Ohms “Law” Resistance (3:14) – Ohms “Law” Resistivity (4:25)

- PhET simulations – DC Circuit Kit – AC Circuit Kit
- Lecture videos
- Definition, Symbols, and Bread Boards (7:11) – Charge Carrier Around the Circuit (4:03) – Circuits - Microsopic (4:55) – Circuits - Power Dissipation (6:42) – DC Circuits 1 - DC Circuit Basics and Real Batteries (6:41) – DC Circuits 2 - Resistors in Series (3:24) – DC Circuits 3 - Resistors in Parallel (4:35) – DC Circuits 4 - Resistor Networks (3:21)

- Example problem videos – batteries with internal resistance (5:00) – equivalent resistance (1:21) – equivalent resistance 2 (4:07)

- Simulations & Interactive Figures
- PhET simulations – Faraday’s Electromagnetic Lab
- interactive swf figures:
- field of a bar magnet (swf)
- magnetic field of a wire (swf)

- videos:
- magneto-hydrodynamics of the sun – Fiery Looping Rain on the Sun
- simulation of the Earth’s magnetic field deflecting solar wind (gif)
- PBS Nova, Michael Faraday (up to 2:26) re-enactment of Faraday’s first electric motor.
- electric motors (5 min)
- Magnetic force on current: Mercury vortex in a magnetic field (gif)
- Magnetic Force Does NOT Exist (4 min), or rather, it is part of an electromagnetic force (if a force disappears when viewed from another perspective, it’s a fictitious force)

- Lecture videos – Magnetic Field - The Big Picture (6:57) – Magnetic Force on a Charge (6:41) – Force - Right Hand Rule (9:26) – Magnetic Force Values (4:24) – Deflecting Charged Particles (5:47) – Radius of the Circular Motion (3:22) – Frequency of the Circular Motion (4:47) – Bouncing from E fields and B fields (4:36) – Non-uniform Magnetic Field (6:31) – Forces on Wires - Preramble (1:17) – Setting Up the Problem (3:03) – Solution for a Straight Wire (5:17) – Solution for a Curved Wire (4:24) – Force on a Square Loop (7:43) – The Loop Moves! (3:42) – Torque on a Square Loop: Qualitative (4:36) – A review of Torque (3:51) – Torque on a Square Loop: Derivation (4:41) – Torque on a Triangular Loop (9:26) – Magnetic Dipole Moment of a Loop (3:59) – Potential Energy of a Loop (6:10)
- Demonstration – Magnetic Force on Charged Particles (1:59) – Electron Beam in a Magnetic Field (2:31)
- Articles – How do you measure a magnetic field? With Hall-effect sensors.
- Example problem videos – Bouncing an Electron off of a Magnetic Field 1 (7:24) – Bouncing an Electron off of a Magnetic Field 2 (3:02) – radius of trajectory, solution (4:26) – force on current, solution (2:12) – force on hanging wire, solution (1:34) – torque on coil, solution (2:23) – Hall Effect, solution (0:41)

- videos:
- MAGNETS: How Do They Work? (6.5 min)
- Paramagnetism and Diamagnetism (4.5 min)
- DIY Electric Train with a battery, spring and magnets

- Lecture videos – Magnetic Field from Current (6:21) – Magnetic Field of a Straight Wire: Set Up (6:21) – Magnetic Field of a Straight Wire: Solution (6:48) – Magnetic Field of a Straight Wire: 3D Structure (3:31) – Statement of Ampere’s Law (6:31) – Ampere’s Law for a Straight Wire (8:55) – Several Amperian Loops (5:52) – The Valentine’s Day Monopole (5:28) – The Ideal Solenoid (5:06) – Amperian Loops Around the Solenoid (5:43) – Ampere’s Law Around the Solenoid (5:28) – Magnetic Fields of a Toroid (4:32)
- Example problem videos – field at the center of a square loop (7:10) – field between 4 parallel currents (3:13) – field from a flat wire (2:46) – field due to a current density (6:15)

- Lecture videos – Faraday’s Induction - Historical Reenactment (4:16) – Faraday’s Law (4:59) – Induction by a Moving Magnet (11:11) – Induction due to Changes in Geometry (2:54) – Move a Conductor in a Magnetic Field (3:49) – Move a Wire Loop in a Uniform Magnetic Field (4:46) – Move a Slider in a Uniform Magnetic Field (1:20) – Induced Electric Field 1 (4:43) – Induced Electric Field 2 (5:11) – Induced Electric Field 3 (5:28) – Induced Electric Field 4 (4:39) – Induced Current Loops also Flow in Solids (6:06) – Examples of Eddy Currents (11:43) – Introduction to the Generator (6:44) – Power Created by a Generator (3:31) – Mechanically Powering a Generator (5:58)
- Example problem videos – induced emf in ring around solenoid (3:36) – induced current in loop near wire (2:13) – induced emf in loop around a toroid (2:59) – current induced in figure 8 wire (2:11) – velocity of slider in circuit (17:24)
- Simulations & interactive swf figures:
- Faraday’s Electromagnetic Lab
- magnetic field flux (swf)
- Lenz’s Law (swf)
- AC generator (swf)
- DC generator (swf)

- videos:
- animated gif:

- Lecture videos – The Inductor (5:14) – Defining Inductance (4:32) – Calculating Inductance (4:25) – LR Circuits 1 - Can’t Apply Kirchhoff’s Rule (3:03) – LR Circuits with Faraday’s Law (7:23) – Differential Equation for the LR Circuit (6:08) – The LR Circuit Solution (4:45) – Discombobulating the LR Circuit (4:45)
- Example problem videos – current in LR circuit (5:11) – LR circuit (6:05) – wire loop rolling down ramp (2:06) – energy stored in solenoid (4:14) – LR circuit - find L and R (4:06) – Differential Equation for an LC Circuit (5:55) – Solution to the LC Circuit (2:42) – Testing Another LC Circuit Solution (1:36) – Testing Yet Another LC Circuit Solution (3:34) – Oscillating Solutions for an LC Circuit (2:11) – LC Circuits - Applying Initial Conditions (3:08) – LC Circuits - Applying Initial Conditions again (4:10) – Differential Equation for the RLC Circuit (4:13) – Damped Charge Oscillations in the RLC Circuit (4:57) – Regimes of Damping of the RLC Circuit (4:42)
- Example problem videos – charge flowing through inductor - pt1 (7:31) – charge flowing through inductor - pt2 (3:16)

- videos – How the Power factor affects the electricity grid (22 min)
- Lecture videos – RLC Response and Impedance (4:53) – RLC Circuits: Current in Each Element (2:47) – RLC Resonance (3:18) – Ampere’s Law Correction (7:11)
- Simulations:
- phet Circuit Construction Kit AC
- simple LRC Circuit sim

- videos:
- Finding The Speed Of Light With Peeps – Standing waves in a microwave oven can be used to measure the speed of light.
- Biographical piece on J.C.Maxwell (10.5 min)
- How Microwaving Grapes Makes Plasma (8 min) demonstrates standing waves in a grape
- Energy doesn’t flow in wires (11 min) The Poynting vector shows that energy is in the fields.

- Simulations: – Radio Waves – Microwave Ovens – Radiating Charge
- Extra Lecture videos – Playlist – Electromagnetic Wave Equation - This is a series of 10 short lectures in which Hafner works from the Maxwell equations he developed previously (see above) to derive the wave equation.

- PhET simulations: – Bending Light (refraction)
- interactive figures:
- interactive swf figures – law of reflection – flat mirror image – curved mirror image – lens images – double polarizers
- simluation of caustics

- videos:
- color and perception
- computer color is broken: vision is logarithmic in intensity, computers are not
- Why you can’t take a good picture of a rainbow (14 min) how the eye perceives color
- sphere is coated in Vantablack, (1 min) the darkest pigment ever, making it look 2 dimensional Vantablack is a substance made of vertically aligned carbon nanotube arrays and one of the blackest artificial substances known, absorbing up to 99.965% of radiation in the visible spectrum.

- why is light slower in glass when c should be constant? (no animation, just a physicist sitting and talking about it)
- “caustics”
- creating an image from “caustic” refraction (3 min)
- optical effects under a wave (gif): a “caustic network”
- how to make caustic images (10 min)

- Bell’s Theorem and polarization (17 min)
- Optical Rotation (18 min) Why Sugar Always Twists Light To The Right – more on that (10 min)
- Using a refractometer to measure water salinity. Also used by home brewers. Light traveling through the sample is either passed through to the reticle or totally internally reflected. The net effect is that a shadow line forms between the illuminated area and the dark area.

- color and perception
- photos:
- news:
- flat metalenses made with nanotubes (a new one that focusses all visible wavelengths)

- PhET simulations: – Lenses and Mirrors
- videos:
- a lens for sound (11 min) made with a balloon
- James Webb Space Telescope assembly (4 min) – article at nasa.gov – article at space.com

- Simulation: Aperture Size and Depth of Field simple interactive figure

- videos:
- Interferometers observe gravitional waves – NY Times on the LIGO discovery
- The Original Double Slit Experiment (7.5 min) a Veritasium video; man takes a two-slit experiment out the beach to let people see the effect

- simulations:
- interactive swf figures: – two-slit interference – multiple-slit interference – michaelson-morley interferometry – michaelson-morley ether wind

- videos:
- How To Make Colour With Holes (5.5 min) – making a diffraction grating
- How Far Can Legolas See?
- Why are Stars Star-Shaped?
- Diffraction from various apertures

- simulations:
- resolution jar file
- single-slit phasor diagrams

- interactive swf figures: – diffraction grating – single-slit interference
- book: If you are looking for some interesting, fairly light reading
over break, consider
*QED: The Strange Theory of Light and Matter*by Richard Feynman. It explains, for a nonscientific audience, how the phasor sum techniques of section 4.2 are how modern Quantum Electrodynamics are formulated. And Feynman is a joy to read. Here are the first 7 pages (pdf).

- The Mechanical Universe – A 1985 television series with 56 half-hour episodes covering first-year Physics. The videos make heavy use of historical dramatizations and visual aids to explain physics concepts. More informtion and episode descriptions at the wikipedia page.

Shockwave Flash (swf) files are no longer playable in modern browsers, due to security problems. You may use the swf files above by saving them, then visiting Ruffle.rs and dragging the swf file into the window there.

*Last modified: November 11, 2024*