[Electrostatics] [Electric Potential, Electric Field, Capacitors] [Resistance, Current]

[Circuits] [Kirchhoff's Rules] [RC Circuits] [Magnetism] [Faraday's Law, Induced EMF] [Lenz's Law, Back EMF, Transformer]

[EM Waves, Light] [Reflection, Refraction] [Lenses, Mirrors] [Eye, Camera, Telescope, Microscope]

[Wave Optics, Thin Films, Interference, Diffraction] [Special Relativity] [Photoelectric Effect, Quantum Mechanics]

[Atom, Pauli exclusion Principle] [Radioactivity, Half-life, Binding Energy] [Dose, Fusion, Fission, TMI]

Electrostatics | |

Electrostatics, Atom, Electron, Proton, Conservation of Charge, Coulomb's Law | Lecture (21 minutes) This video describes concepts of electrostatics, the structure of the atom, Franklin's view of electricity, Millikan's measurement of the charge of the electron, conductors, insulators, charging by induction, Coulomb's Law. |

Electrostatics: Concepts Related to Charges | Concepts (6 minutes) This video highlights some important concepts about charge. There are no calculations in this video. The video discusses: the fundamental unit of charge, the charge values of protons and electrons, the discrete (quantized) nature of charge. |

Electrostatics: Concepts of Electric Force | Concepts (6 minutes) This video discusses concepts related to electrical force between two charged objects. The video discusses: repelling, attracting, dependence of the size of the force on the size of the charges, the force is inversely proportional to the square of the radius (weaker as distance squared increases), and the direction of the force. |

Electrostatics: Number of Electrons in a Penny Coin | Example (5 minutes) This video calculates the number of electrons in a penny made of pure copper atoms that have 34 neutrons in the nucleus. The mass of the penny, grams per mole, and Avogadro's Number are used to calculate the number of atoms. The number of electrons in one atom equals the number of protons in the atom. |

Electrostatics Force On Charges | Example (4 minutes) This example problem in electrostatics calculates the force on a fixed charge due to another fixed charge. Coulomb's Law is used. The video also discusses the force on the second charge due to the first charge. |

Electrostatics: Charge on Earth and Moon to Replace Force of Gravity | Example (5 minutes) This video calculates the magnitude of net charge on the Earth and Moon that would create a force equal to the current gravitational force between the Earth and the Moon. |

Two Charges Repel, Touch, Repel | Example (13 minutes) This video shows how to calculate the values of charges for the situation where the repelling force and separation distance are known but the individual, different, values of the charges are not known. The metal objects touch and then are separated and a new value for the repelling force is given. |

Two Charges Attract, Touch, Repel | Example (14 minutes) This video shows how to calculate the values of charges for the situation where the force and separation distance are known but the individual, different, values of the charges are not known. The objects initially attract. The metal objects touch and then are separated and a new value for the repelling force is given. |

Electrostatics: Location Where Net Force on Third Charge Is Zero | Example (13 minutes) This electrostatics example calculates the location where a third charge can be placed in relation to two fixed charges such that the net force on the third charge is zero |

Electric Field near a Conductor, Applications of Electrostatics | Example (8 minutes) This video discusses the properties of electric field near a conductor and the effect on charge in the conductor. The video shows the nature of electric field for conductors that are not spheres. The electric field of the Earth, lightning, and lightning rods are discussed. Some applications of electrostatics are discussed. This material relates to Chapter 18 of OpenStax, General College Physics 2 |

Electrostatics...Where is E = 0 for three charges on X axis | Example (11 minutes) An approximate solution is found for the location where the electric field = 0 for the case of three charges on the x axis. First we reason where the electric field might be zero. Then we write the expression to calculate the electric field. Then we calculate the net electric field for integer X values in the target region. |

Electrostatics Zero Net Force on Third Charge when 2 fixed charges are present | Example (5 minutes) Consider two fixed charges on the x axis. This video shows how to find the location where a third charge could be placed on the x axis such that the net force is zero |

Electrostatics Calculate Potential and Work Done in Moving a Second Charge | Example (4 minutes) A fixed charge is located on the X axis. Calculate the potential at two locations on the X axis. Calculate the work done in moving a second charge from one location to another location on the x axis. Calculate the work done in moving a different charge from one location to infinity. |

Electrostatics Work Required to move a Third Charge with 2 fixed charges | Example (4 minutes) Two fixed charges are on the x axis. We want to calculate the work required to move a third charge from one location to another location on the x axis. Before calculating the work we must calculate the potential at each location due to the two fixed charges |

Electrostatics, Two Charged Metal Spheres on Strings Repel Each Other | Example (13 minutes) This video calculates the size of the charge on each of two metal spheres that are repelling each other. The concept of static equilibrium is used to write an equation for the X direction and an equation for the Y direction. The equations are combined to eliminate the unknown tension in the strings. Coulomb's Law is used to calculate the charge value |

Electrostatics, Electric Field From Force and Charge Values | Example (11 minutes) This video calculates the value of the electric field due to a metal object that carries an unknown charge. A metal sphere carries the same sign of charge as the metal object. The electric force is calculated based on the distance the sphere is from the object and the length of the string holding the sphere. |

... | Return to the top of this page. ... OR ... Return to physics.gpclements.com |

Electric Potential, Electric Field, Capacitors | |

Electrostatics Potential Work OS Chp 19 1 | Lecture (8 minutes) Discussion of Chapter 19 Section 1 of OpenStax College Physics. The topics are electric potential, work, potential energy, joules, electron volts. |

Electrostatics Potential E Field Chp 19 Sections 2 3 4 | Lecture (9 minutes) Discussion of Sections 2, 3 and 4 of Chapter 19 in the OpenStax College textbook. Topics include E field and potential difference, lines of equipotential, calculating potential, drawing E field lines across lines of equipotential. |

Proton between two plates Calculate KE, velocity, Electric Field Strength, Potential | Example (5 minutes) A proton is very near a plate at 25 kV potential. The other plate, 0 kV, is 50 cm away. Calculate the KE of the proton the instant it hits the 0 kV plate and the speed of the proton. Calculate the strength of the electric field and the potential at a point between the two plate. |

Electric Field Between the Plates of a Capacitor | Example (7 minutes) This video calculates the value of the electric field between the plates of a parallel plate capacitor. The area of the plates and the charge on the plates is given but not the potential difference between the plates. Three equations are combined to derive the equation used to calculate the electric field. |

Derive Formula for Capacitance of Parallel Plate Capacitor | Concept (11 minutes) This video shows the derivation for the formula for capacitance for a parallel plate capacitor. Gauss' Law is used to determine the formula for the electric field inside the capacitor. This derivation assumes a uniform electric field. The edge effect of a bending electric field is ignored. The capacitance formula only contains area, distance between the plates and the electric constant epsilon naught. |

One Farad Capacitor, Physical Size, Dielectric | Example (8 minutes) This video calculates the area of square plates for a 1 Farad capacitor with plates separated by 1 mm. Then the length of one side is calculated. The video discusses how a smaller 1 Farad capacitor can be manufactured by using dielectric and a smaller separation of the plates |

Capacitor Calculations, Capacitance, Charge, Voltage, Dielectric | Example (9 minutes)This video calculates the capacitance from the area and separation of the parallel plates. The video calculates the charge on the plates when the capacitor is connected to a battery. The value of the capacitance and potential between the plates is calculated when dielectric is inserted between the plates. |

Capacitors Series and Parallel Network Find Equivalent Value of Single Capacitor | Example (3 minutes) Three capacitors are connected. We desire to know the value of the single, equivalent capacitor. |

Capacitors Dielectrics Series Parallel | Lecture (15 minutes) Explanation of capacitors...Concepts, Calculation of Capacitance value, Effect of Dielectrics, Capacitors connected in Series, Capacitors connected in Parallel, Energy stored in a capacitor. |

Electric Potential Due to 3 Charges and Work to Move another charge to infinity | Example (5 minutes) Three charges are placed on a X Y coordinate system. The net potential at a location is calculated. The work to move a fourth charge from this location to infinity is calculated. |

... | Return to the top of this page. ... OR ... Return to physics.gpclements.com |

Resistance, Current | |

Current Resistance Ohms Law Resistivity OS Chp 20 sections 1 2 3 | Lecture (16 minutes) Discussion of Resistance, Ohm's Law, Resistivity. This material is found in the OpenStax College physics text Chapter 20 sections 1,2,3 |

Power in Resistor Circuit, Alternating Current, Electrical Safety | Lecture (8 minutes) Power in electrical circuit, AC concepts, Electrical Safety. This material is taken from OpenStax College Physics chapter 20 sections 4,5,6 |

Resistance, Current, Power example for a carbon rod attached to a battery | Example (3 minutes) A carbon rod that has a length of 3.6m and a diameter of 6mm is attached by ideal wires to a 6V battery. Calculate the resistance of the carbon rod, the current leaving the battery, and the power delivered to the carbon rod. |

Current calculated from charge and time, resistance, power example | Example (3 minutes) An unknown resistance is attached to a 6V battery. The charge passing through the resistor is 2.7 Coulombs for an elapsed time of 32 seconds. Calculate the current, the resistance value, and the power delivered to the resistor. |

Resistance, Current, Power in a circuit | Example (3 minutes) A 9 volt battery is connected to an aluminum rod that has a length of 2.8 km. The diameter of the rod is 2 mm. Calculate R, I, and the power delivered to the rod. |

Potential Difference, Circuit, Three Branches, Batteries, Resistors | Example (8 minutes) A circuit consists of batteries and resistors. The circuit has an outer loop and an inner stub connected at only one end to the outer loop. The potential difference between the outer loop and inner stub is calculated. |

... | Return to the top of this page. ... OR ... Return to physics.gpclements.com |

Circuits | |

Resistors in Series and Parallel, Batteries Internal Resistance, Chapter 21 Sections 1,2 | Lecture (14 minutes) This video describes how to simplify circuits that contain series and parallel combinations of resistors. The video also describes batteries and how they function when connected in series or in parallel. |

Battery Resistors Series Parallel Power in Each Resistor | Example (5 minutes) A 12 volt battery is connected to a 1 ohm resistor and a parallel connection of 6 and 13 ohms. The current in each resistor is determined. The power in each resistor is found using P = I V. The results at each step of the calculation are checked for reasonableness. |

Circuit with battery, wires with resistance, and parallel resistor network, Calculate Power | Example (4 minutes) A 9 volt battery is connected to three 18 ohm resistors arranged in parallel. The wire that connects the resistors has a resistance of 2 ohms. Calculate the power in the resistors and wire, and calculate the % of wasted power. |

Calculate the value of an external resistor given the current, emf, and internal resistance value | Example (3 minutes) A 9 volt battery has an internal resistance of 0.6 ohms. When the battery is connected to an unknown external resistor the current from the battery is 300 mA. What is the value of the external resistor? |

Battery Internal Resistance when new and when old | Example (4 minutes) The ability of a battery to deliver current to a circuit decreases as the internal resistance increases. The current and terminal voltage is calculated for a new and old 9 volt battery connected to a 7 ohm resistor. |

... | Return to the top of this page. ... OR ... Return to physics.gpclements.com |

Kirchhoff's Rules, Meters | |

Determine Currents For Simple Circuit Using Two Methods | Example (13 minutes) A circuit consists of a parallel set of resistors that are in series with another resistor and a battery. The currents in each branch of the circuit are determined. First the resistor network is simplified and V=IR is used to find the currents. The second method uses Kirchhoff's Laws for Circuits to solve for three unknowns with three equations. |

Concepts of Circuit Analysis Using Kirchhoff's Rules | Lecture (11 minutes) This video discusses the use of Kirchhoff's Rules to solve for the currents in branches of a circuit. Circuits that cannot be simplified using the rules for series and parallel resistance can be analyzed using Kirchhoff's Rules. This video only discusses the rules and concepts that will be used to solve for the currents in each branch of the circuit. Please look for my video that shows how to solve a circuit using Kirchhoff's Rules. |

Another Kirchhoff's Circuit Laws Example | Example (18 minutes) This video shows how to calculate the current in each branch of a circuit. The circuit includes three branches and two batteries. This circuit cannot be solved using simple series and parallel resistor combinations. The voltage and current laws are used to generate three equations for the three unknowns. This system of equations is solved using algebra techniques. The meaning of a negative current is discussed. The values of the currents are inspected to see if they are reasonable |

Circuit, Determine Six Unknown Currents Using Kirchhoff's Laws | Example (15 minutes) A resistor network is connected to a 20 volt battery. Due to the connections of the resistor network the circuit cannot be solved using parallel and series simplifications. Kirchhoff's Laws for Circuits are used to create six equations. The six unknown currents are determined using substitution and elimination. The solution is verified. |

Circuits: Concepts of Using Voltmeters and Ammeters | Lecture (5 minutes) This video gives a general discussion of the properties of voltmeters and ammeters and how they are used in circuits. |

Voltmeters Ammeters Null Measurements | Lecture (14 minutes) This video discusses the use and construction of simple voltmeters and ammeters. Null measurement techniques for EMF and resistance are discussed. The resistance null measurement is done in a Wheatstone bridge circuit. |

Solving for Currents using Kirchhoff's Rules for Circuits | Example (12 minutes) A circuit consists of three branches. The top branch has a 6V battery in series with a 2 ohm resistor. The middle branch has a 3V battery in series with a 5 ohm resistor. The bottom branch has a 7 ohm resistor. The junction rule and sum-of-potentials-around-a-loop are used to write three equations. Algebra is used to solve for the three unknown currents |

NULL Technique to determine EMF of an unknown battery | Example (7 minutes) The EMF of an unknown battery can be determined if a known EMF is available. This video discusses a simple circuit for experimentally determining the EMF. A separate power supply or stable battery creates a current in a potentiometer. The standard or unknown EMF is placed in parallel with a section of the potentiometer. The resistance of the section of the potentiometer is adjusted until the current is zero in the standard or unknown battery. This allows us to write down two equations using voltage = I R. The equations are divided and simplified to show how the unknown EMF can be calculated. |

Wheatstone Bridge Concepts: Calculate the Value of an Unknown Resistance | Example (7 minutes) This video describes the concepts of the Wheatstone Bridge. The circuit is used to find the value of an unknown resistance. Four resistors are used. Two resistors in series are connected in parallel with two other resistors that are in series. Refer to the diagram in the video if the previous sentence is not clear. A galvanometer is connected between each series pair of resistors. One of the known resistors is adjusted until the current in the galvanometer is zero (this is the null part of the concept). The two equations that relate the voltage drops across resistors can be divided to provide the equation used to calculate the value of the unknown resistance (see the video for details). |

... | Return to the top of this page. ... OR ... Return to physics.gpclements.com |

RC Circuit | |

RC Resistor Capacitor Circuits Charge Discharge | Lecture (7 minutes) This video discusses RC circuits. A resistor and capacitor are connected in series. The capacitor is charged by placing a battery in the circuit. A charged capacitor is discharged by closing a switch to complete a circuit. The motion of electrons is discussed. The connection between the potential difference across the capacitor and the charge on the capacitor is discussed. |

RC Circuit Charging and Discharging Calculations | Example (8 minutes) This video describes how to calculate the potential across a capacitor at some specified time after the capacitor is connected through a resistor to a battery. The video also describes how to calculate the time required for the potential across a capacitor to drop to a given value after the capacitor is connected to a resistor. |

Another RC Circuit, Discharge Time | Example (11 minutes) This video shows calculations that apply to a resistor connected to a capacitor that is carrying charge. The calculations include: voltage of the capacitor before discharge, voltage of the capacitor at a certain time, the time required for the current in the resistor to reach a given value. The non-linear nature of the voltage vs. time characteristic for the capacitor is discussed. |

... | Return to the top of this page. ... OR ... Return to physics.gpclements.com |

Magnetism | ||

Magnetism Permanent Electromagnets Magnet Force Circular Motion Concepts | Lecture (21 minutes) This video discusses the concepts of permanent and electromagnets. The traditional right hand rule is used to determine the direction of force on a charged particle. The magnetic force can create a centripetal force resulting in uniform circular motion. The Earth's magnetic field and aurora are briefly discussed. | |

Magnetic Force on a Moving Proton Due to A Given Magnetic Field | Example (6 minutes) A proton is moving west at 1.7 x 10^6 m/s. The magnetic field is 0.07 Teslas directed to the south. The magnitude and direction of the force on the proton are discussed. For the second part of the problem the magnetic field is 0.07 Teslas directed to the west. The value of the force is discussed. | |

Radius of Circular Motion for Electron Moving in a Uniform Magnetic Field | Example (8 minutes) An electron is traveling east at 8 x 10^6 m/s. The magnetic field is to the south with a strength of 0.025 Teslas. The magnetic force is perpendicular to the velocity and provides a centripetal force. The radius of the circular motion is calculated. Note...I misspoke and said a proton has low mass...this problem dealt with an electron...which is even less massive than a proton! This material relates to Chapter 22 of OpenStax College Physics (8 minutes) | |

Hall Effect Magnetic Force Torque Coil Solenoid Mass Spectrometer | Lecture (12 minutes) This video discusses the Hall Effect, Magnetic Force on a long straight wire, Torque on a loop that has current in the presence of a magnetic field, magnetic field created by a coil and by a solenoid, force between two parallel wires, and the mass spectrometer. The PowerPoint is from OpenStax College Physics. | |

Direction of Magnetic Force on a Moving Charged Particle | Concept (5 minutes) This video shows 4 examples of charged particles moving in a region of uniform (constant) magnetic field. The use of the right hand rule is discussed and the direction of the force is described. Chapter 22 OpenStax College Physics. | |

Magnetic Force on A Moving Electron | Example (7 minutes) This video shows how to find the direction of the magnetic force on a particle that has negative charge. The video calculates the radius of the circular path of the electron. The video discusses the speed of the electron as it moves around the circular path. | |

Mass Spectrometer, Magnetic Force, Electric Force | Example (12 minutes) This video shows calculations that apply to a mass spectrometer. The strength of the electric field for the velocity selector is calculated. The mass of the singly ionized atom is calculated. The number of grams per mole for the atom is calculated and a guess is made as to the element name. | |

Magnetic Field Due to a Straight Wire Carrying Current | Example (5 minutes) This video shows how to calculate the strength of the magnetic field due to a straight wire. The current and distance from the wire are given in the problem. The Right Hand Rule is used to determine the direction of the magnetic field. | |

Magnetic Force on a Wire That is Carrying Current | Example (5 minutes) This video describes how to calculate the strength and direction of the magnetic force on a wire that is carrying current. The Right Hand Rule is used to determine the direction of the force. | |

Mass Spectrometer Velocity Selector and Impact Locations for Two Isotopes of Chlorine | Example (12 Minutes) This video shows how to calculate the speed of ions passing through a velocity selector. Then the video shows how to calculate the impact locations in a mass spectrometer for two isotopes of Chlorine: Cl-35 and Cl-37. | |

Velocity Selector, Charge to Mass Ratio for Electron | Example (11 minutes) This video describes a velocity selector in which the electrical and magnetic forces on an balance each other for electrons moving at the proper speed. The speed is determined using the potential difference between the metal plates, the distance between the plates, and the strength of the magnetic field. Those electrons travel in a straight line and then enter a region in which only a magnetic field exists. The magnetic force provides the centripetal force for the electrons. The diameter of the circle, the strength of the magnetic field, and the speed of the electrons allow for the calculation of the charge to mass ratio for the electron. | |

Solenoid | Example ( 8 minutes) This video calculates the number of turns of wire per meter needed to create a given magnetic field strength. A simplified version of Ampere's Law is used. The current in the wire is given. | |

... | Return to the top of this page. ... OR ... Return to physics.gpclements.com |

Faraday's Law, Induced EMF | |

Induced EMF, Current, Magnetic Flux, Generators | Lecture (19 minutes) This video discusses the concepts of magnetic flux, induced EMF and current, and Lenz's Law. Eddy currents, magnetic braking, and electrical generators are also discussed. td> |

Induced EMF, Current, Rod Moving on Horizontal Rails | Example (13 minutes) Faraday's Law is used to calculate the EMF induced when a rod moves along two horizontal rails in the presence of a magnetic field. Ohm''s Law is used to calculate the current in the circuit. Lenz's Law is used to determine the direction of the current. |

AC Generator, Spinning Coil of Wire in a Magnetic Field | Example (7 minutes) This video shows how to calculate the revolutions per minute speed for a coil rotating in a magnetic field to produce a given maximum voltage. The video also calculates the average EMF for one-quarter spin. The video discusses how to make the maximum EMF larger and points out the AC nature of the EMF. |

Induced EMF and Current in a Coil of Wire Due to a Changing Magnetic Field | Example (8 minutes) This video shows how to compute the value of the induced EMF (volts) due to a changing magnetic field. The coil has 26 turns of wire and a radius of 12 cm. The magnetic field is directed upward through the coil and has an initial strength of 2.4 x 10^-3 Tesla. After 1.7 seconds have elapsed the magnetic field value is 3.9 x 10^-3 Tesla, still directed upward through the coil. The average value of the EMF is calculated. The direction of the induced current is found using Lenz's Law and the Right Hand Rule. |

Induced EMF Due To Changing Area | Example (12 minutes) Faraday's Law is used to calculate the EMF induced when a rod moves along two horizontal rails in the presence of a magnetic field. Ohm''s Law is used to calculate the current in the circuit. Lenz's Law is used to determine the direction of the current. |

... | Return to the top of this page. ... OR ... Return to physics.gpclements.com |

Lenz's Law, Back EMF, Transformer | |

Back EMF, Current and Power in a Motor | Example (4 minutes) This video briefly describes what causes "Back EMF" in a spinning electric motor. The video shows a calculation for the current and power in the motor for the case of the motor not spinning and the motor spinning at full speed. |

Back EMF, Transformers, Electrical Safety, Inductors | Lecture (14 minutes) This video describes back EMF for the case of a refrigerator. The video also discusses the construction and operation of a transformer. Electrical safety and inductors RL and RLC circuits are briefly discussed. |

Electrical Transformer with AC and DC Applied to the Primary Coil | Example (5 minutes) A transformer is constructed with 200 turns on the primary coil and 10 turns on the secondary coil. The video shows how to calculate the voltage across the secondary coil for various AC voltages on the primary coil. The behavior of the transformer for a DC voltage on the primary is briefly discussed. |

... | Return to the top of this page. ... OR ... Return to physics.gpclements.com |

EM Waves, Light | ||

Electromagnetic Waves, Maxwell's Equations, Speed of Light | Lecture (18 minutes) This video introduces electromagnetic waves. Maxwell modified Ampere's Law for Magnetism and then combined the equations of electricity and magnetism to predict the existence of an electromagnetic wave. The speed of this wave matches the measured speed of light. OpenStax College Physics Chapter 24. | |

Production of Electromagnetic Waves (Classical Physics) | Lecture (5 minutes) This video discusses the generation of electromagnetic waves due to the acceleration of charge. Hertz experiment to detect EM waves is also presented. Chapter 24 Part 2, OpenStax College Physics. | |

Electromagnetic Spectrum | Lecture (10 minutes) This video discusses the electromagnetic spectrum from gamma rays to radio waves. Some uses and dangers of different portions of the EM spectrum are discussed. The greenhouse effect and ozone layer of the Earth's atmosphere are discussed. | |

Electromagnetic Waves: Wavelength and Frequency, Distance and Time of Travel | Examples (15 minutes) This video shows example problems where frequency and wavelength of electromagnetic waves are calculated. The video also shows calculations of distance = rate * time where the rate is the speed of light. | |

Speed of Light, Wavelength, Frequency | Example (4 minutes) This video (unnecessarily) calculates the speed of light in a vacuum given the wavelength and frequency. The speed of light in a vacuum is the same for all wavelengths. The video calculates the frequency for UV light. | |

Intensity and Power Received for a Radio Station Broadcast, and Laser Intensity | Examples (7 minutes) This video calculates the power passing through a 0.6 m^2 area due to a 55,000 Watt radio transmitter at distances of 15 and 30 km. The video also calculates the intensity of a 0.5 mW laser which has a beam width of 0.8mm. | |

... | Return to the top of this page. ... OR ... Return to physics.gpclements.com |

Reflection, Refraction | ||

Geometrical Optics, Reflection, Refraction, Total Internal Reflection, Corner Reflector | Lecture (26 minutes) This video starts the series of lectures on geometrical optics. In this material the optical elements are much larger than the wavelength of the light. The video discusses the concept of rays, specular reflection, diffuse reflection, index of refraction, Snell's Law, total internal reflection, and corner reflectors. OpenStax College Physics. | |

Reflection Reflected Angle For Turning Mirror | Example (8 minutes) This video calculates the angle of reflection when a mirror turns through a small angle. The incoming ray has a fixed position. The video also discusses how to do the calculation if the wavelength of incoming ray changes. | |

Reflection From a Rotated Mirror | Example (10 minutes) This video reviews reflection from a flat mirror. The reflected angle is determined for red and blue light. The mirror is rotated and the new direction of the reflected ray is determined. The fact that the change in direction of the ray is double the rotation angle of the mirror is discussed. | |

Reflection of Light, Mirrors at Right Angles, Corner Reflector | Example (8 minutes) This video shows the path of an incoming ray to a system of two mirrors joined at a right angle. This system is called a corner reflector. Only a two dimensional corner reflector is discussed here. The direction of the ray that exits the system is compared to the direction of the ray that entered the system. The uses of corner reflectors on bicycles and on the Moon are discussed. | |

Refraction of a Ray Passing Through a Rectangular Piece of Glass | Example (10 minutes) This video calculates the angle of a ray inside a piece of glass due to a ray in air striking the glass. The angle of the ray from the normal in air is given. The index of refraction is discussed and the values for air and glass are given. The video continues by calculating the angle of the ray as it exits the glass back into the air. | |

Refraction, Red and Blue Light Through Rectangle of Glass | Example (13 minutes) This video calculates the angles of refraction for two colors of light as the light refracts in a glass rectangle. Snell's Law is used. The meaning of the index of refraction is briefly discussed. The distance between the two exit location for the rays of light is calculated. The angles of the two rays in air as they exit the glass rectangle are calculated. | |

Refraction of Light Through a Prism (One Wavelength) | Example (10 minutes) This video calculates the angle of a ray in class given the indices of refraction (air, glass) and the angle of the incoming ray. The video also calculates the angle of the ray as it exits the glass on the other side of the prism. | |

Refraction of Ray in Triangle Producing Total Internal Reflection | Example (10 minutes) This video calculates the refraction of a ray that starts in air and goes into an equilateral glass triangle. The ray in the glass that strikes the second side of the triangle undergoes total internal reflection. The reflected ray strikes the base of the triangle and reflects out into the air. | |

Dispersion, Refraction of Blue and Red Light across an Equilateral Triangle of Glass | Example (10 minutes) This video calculates the refraction angles for blue and red light with given indices of refraction. The blue light exits into the air at a greater angle than the red light. | |

... | Return to the top of this page. ... OR ... Return to physics.gpclements.com |

Lenses, Mirrors | ||

Dispersion, Images Formed by Converging and Diverging Lenses, Simple Magnifier | Lecture (16 minutes) This video discusses dispersion with examples of rainbows and prisms. The video continues with discussion of ray tracing for converging and diverging lenses. The simple magnifier and the case of two lenses is briefly discussed. | |

Image Formed by Converging Lens, Ray Tracing and Calculation of Position and Image Height | Example (8 minutes) This video shows how to use ray tracing rules to locate the image formed by a converging lens. The image position is also calculated. The magnification is calculated and the image height is calculated. | |

Image Formed by Two Converging Lenses, Ray Tracing, Calculations | Example (11 minutes) This video shows how to locate the first and final images for the case of two converging lenses. The video also shows how to calculate the first and final image locations and the height of the final image. | |

Geometrical Optics, Image Formed by Converging and Diverging Lenses | Example (13 minutes) The location of the final image formed by the action of a converging lens and a diverging lens is found by ray tracing and by calculation using the equation for a thin lens. The image formed by the first lens is the object for the second lens. The sign convention is discussed. The magnification and image height are calculated. | |

Images formed by Flat, Concave, Convex Mirrors | Lecture (8 minutes) This video discusses the formation of images by flat, concave, and convex mirrors. Ray tracing is used to locate the images. Section 7 of Chapter 25 of OpenStax College Physics. Lecture | |

Two Mirrors at Right Angles have Three Images of the Object | Example (9 minutes) This video shows the ray tracing that locates the three images of an object that is in front of two mirrors joined at right angles. There are no calculations in this video. td> | |

Concave Mirror, Ray Tracing to Locate Image and Calculation | Example (6 minutes) This video shows how to find the image location for an object in front of a concave mirror where the object distance is greater than the focal length. The video also shows how to calculate the image location. td> | |

Convex Mirror, Ray Tracing to Locate Image and Calculation | Example (6 minutes) This video shows how to find the image location for an object in front of a convex mirror where the object distance is greater than the focal length. The video also shows how to calculate the image location. td> | |

... | Return to the top of this page. ... OR ... Return to physics.gpclements.com |

Eye, Camera, Telescope, Microscope | ||

Eye Optics, Nearsighted Farsighted | Lecture (11 minutes) This video discusses how the eye forms a focused image on the retina. The video also discusses the cause and correction for nearsightedness and farsightedness. Chapter 26 of OpenStax College Physics. | |

Nearsighted Eye, Lens and Contact Lens to See Distant Object | Example (5 minutes) A nearsighted person is able to see distant objects clearly with the aid of a -4.7 diopter lens 1.9 cm from the eye. The power of a contact lens is determined that also allows the person to see distant objects clearly. | |

Farsighted Eye Needs Lens to Read Close Book | Example (6 minutes) An eye needs a +2.2 diopter lens in order to read a book that is 26 cm from the eye. The position of the book for reading without the lens is determined. A brief discussion is given as to why the lens helps in reading the book. | |

Camera With Fixed Focal Length Lens and Objects at Two Distances | Example (8 minutes) A SLR camera has a lens with a fixed focal length. The position of the lens from the sensor is determined such that objects at different distances are in focus. | |

Microscope, Two Converging Lenses | Lecture (5 minutes) This video discusses the operation of a simple microscope. Two short focal length lenses are used to construct the microscope. Chapter 26 of OpenStax College Physics | |

Telescopes, Refractors, Reflectors, History of Telescopes, Hubble Telescope | Lecture (17 minutes) This video describes refracting and reflecting telescopes. Some history of telescopes is included in the video. Chapter 26 of OpenStax College Physics. | |

Corrective Lenses for the Eye Nearsighted and Farsighted | Example (7 minutes) This video shows calculations of the power (in diopters) for corrective lenses for both a nearsighted and farsighted eye. The lens is assumed to be 2 cm from the eye. Chapter 26 of OpenStax College Physics. | |

Microscope, Two Converging Lenses, Ray Tracing and Calculations | Example (8 minutes) This video discusses a microscope made of two short-focal length converging lenses. The object location and focal lengths are given. Ray tracing is performed to locate the final image. The location of the final image is located and the magnification is calculated. | |

Telescope Magnifcation and Light Gathering Power Comparison | Example (7 minutes) This video shows how to calculate the magnification value for a telescope. The video also shows how to calculate how much light the Hubble telescope gathers compared to a typical amateur astronomer's telescope. | |

... | Return to the top of this page. ... OR ... Return to physics.gpclements.com |

Wave Optics, Interference, Diffraction, Thin Films | ||

Wave Optics, Interference, Huygens, Double Slit | Lecture. (17 minutes) This video starts a discussion of wave optics. In wave optics the light is interacting with objects that are small...a few millimeters or less. Some examples of interference are presented. Huygen's Principle is explained. Constructive and destructive interference of the case of a double slit is discussed. The observation of interference for light in the early 1800's gave proof that light travels as a wave. Chapter 27 of OpenStax College Physics. | |

Double Slit Interference Maxima and Minima Locations | Example (10 minutes)This video discusses the interference pattern formed by a double slit. The location of the second order maximum and the second minimum are calculated. | |

Interference for Double Slit, Location of Maximum for Close Slits | Example (9 minutes) This video discusses that the expected maximum may not exist for a double slit if the slits are too close together or the order number (m) is too high. The location of the m=1 and m=2 maxima are calculated. It is noted that the angles for m=1 and m=2 are not linearly proportional because sine is not a linear function. Chapter 27 in OpenStax College Physics. | |

Diffraction Grating, Iridescence, Single Slit Diffraction, Missing Orders | Lecture (20 minutes) This video discusses diffraction gratings, iridescence, and diffraction from a single slit. The formation of narrow maxima by the diffraction grating is explained. Examples of iridescence are shown. Destructive interference and the location of minima for the single slit are explained. Missing orders are discussed. | |

Diffraction Grating, Location of First Order Maximum on a Screen | Example (7 minutes) This video shows how to calculate the distance between adjacent slits for a diffraction grating where the number of lines per inch is given. Then the video shows how to calculate the location on a screen of the first order maximum. | |

Single Slit Diffraction, Location of Minima | Example (6 minutes) This video shows how to calculate the location of minima on a screen due to monochromatic light passing through a single slit. This material relates to Section 5 of Chapter 27 of OpenStax College Physics. | |

Double and Single Slit Effects, Missing Order | Example (11 minutes) This video calculates the angles to the first 6 maxima for a double slit. The video then calculates the angles to the first 2 minima for the single slit diffraction pattern. It is noted that one of the maxima has an angle equal to the angle of a minima in the single slit diffraction pattern. The concept of a missing order is explained. Chapter 27 of OpenStax College Physics. | |

Interference Diffraction Find Slit Separation | Example (10 minutes) Nine maxima of the double slit interference pattern are observed inside the width of the central maximum of the single slit pattern. The width of each slit is 0.0125 cm. A minimum of the double slit interference pattern has the same location on the screen as the first minimum of the single slit diffraction pattern. The wavelength is unknown. The separation of the two slits is determined. | |

Double Slit Interference, Calculate Wavelength | Example (9 minutes) This video shows how to calculate the wavelength of light falling on a double slit when the distance between two maxima is given. Also given are the slit separation and the distance from the slits to the screen. | |

Resolution, Thin Films, Polarization | Lecture (27 minutes) This video discusses the concepts or resolution, thin film interference and polarization. The Rayleigh Criterion for resolving objects is explained. The method for determining whether constructive or destructive interference occurs for a thin film is explained. The nature of polarized light and the operation of Polaroid filters are explained. Chapter 27 of OpenStax College Physics. | |

Resolution Angle, Rayleigh Criterion | Example (11 minutes) This video calculates the minimum angle of separation in order to see two objects using the Hubble Telescope and your eye. The video also shows how to calculate the diameter of a telescope on Earth that would be useful in resolving objects for the case of the "seeing" (twinkling of atmosphere) of 3 arcseconds. | |

Thin Film Interference | Example (9 minutes) This video calculates the minimum thickness of a layer of glycerine on flint glass for which light of wavelength 600 nm is not seen in the reflection. The video discusses phase shift at reflection, phase shift due to path length, and the new wavelength in the glycerine. | |

Thin Film Interference for a Soap Bubble | Example (10 minutes) This video shows how to calculate the thickness of a soap bubble for which we see 500nm light enhanced over other colors. The video discusses phase shift at reflection, changing wavelength in a medium, and phase shift due to path length. The video includes a comment near the end as to why the colors on a soap bubble shift around as you view the bubble. | |

Polarization Intensity Calculations | Example (7 minutes) This video briefly discusses the concept of how polarized light is produced from unpolarized light using a Polaroid filter. The video shows how to calculate the intensity of light that exits a Polaroid filter based on the angle of rotation of the Polaroid filter with respect to the polarization direction of the EM wave. | |

... | Return to the top of this page. ... OR ... Return to physics.gpclements.com |

Special Relativity | ||

Special Relativity, Simultaneous Events, Time Dilation, Length Contraction | Lecture (19 minutes) This video gives some background on Einstein and then discusses simultaneous events, time dilation, and length contraction. This material relates to Sections 1 - 3 of Chapter 28 of OpenStax College Physics. | |

Special Relativity: Postulates, Time, Length, Speed Limit, E=mc^2 | Lecture for Descriptive Astronomy class (23 minutes)This video discusses Special Relativity (motion at a constant speed). Special Relativity predicts that moving clocks run slow, moving lengths are shorter, objects that have mass cannot move as fast as the speed of light, and mass can become energy. No experiments disagree with the predictions. This material relates to Chapter 6 of astronomynotes.com Some slides from OpenStax College Physics are used. Introductory Astronomy class | |

Special Relativity, Calculating the Gamma Factor | Example (8 minutes) This video shows how to calculate gamma for certain speeds of an object. The video also comments on the results. Gamma is used in calculations for Special Relativity. | |

Special Relativity, Time Dilation | Example (7 minutes) This video shows how to calculate the effect of time dilation...moving clocks run slower than a clock at rest. An observer on Earth will see less time elapse on a clock on a fast spacecraft compared to a clock at rest in the observer's frame of reference. The value of the elapsed time on the moving clock is calculated by dividing the elapsed time for the clock at rest by the factor gamma. | |

Special Relativity, Time Dilation, Calculate Velocity Given Times | Example (9 minutes) This video shows how to calculate the velocity of a spacecraft when you are given the observed elapsed time for a clock on the spacecraft and the elapsed time for a clock held by the observer. The elapsed time on the moving clock is less than the elapsed time for the observer's clock. The factor "gamma" is used to find the velocity. There are brief comments about the validity of the answer and the speed of real spacecraft. | |

Special Relativity, Length Contraction | Example (3 minutes) This video shows how to calculate the length of a moving object. The length of an identical object at rest with respect to the observer is given. The speed of the moving object is given. The length of the moving object is reduced by the factor of gamma. | |

Special Relativity, Time to Travel to A Distant Star, Twin Paradox | Example (10 minutes) This video shows how to calculate the travel time to a distant star for a spacecraft moving at 0.98c. The video calculates the time dilation and discusses the ages of a person who remains on the Earth compared to the person who is in the spacecraft. The Twin Paradox is discussed and the solution is discussed. | |

Special Relativity, Velocity Addition | Example (6 minutes) This video shows how to add velocities for the case of high speed. The result is much different than the result for addition using the concepts of Classical Physics. The velocity addition formula for Special Relativity has a result that is never larger than the speed of light. | |

Special Relativity, Calculating Speed Given New Length of Spacecraft | Example (7 minutes) This video shows how to calculate the speed of a spacecraft that is observed to be shorter than it was before launch. The length contraction concept is used to find the value of gamma. The formula for gamma is used to calculate the speed of the spacecraft. | |

Special Relativity, Velocity Addition, KE, Speed Limit, Correspondence Principle | Lecture (15 minutes) This video discusses the concept of velocity addition at high speeds. The video also discusses relativistic KE and the limit on speeds for objects that have mass. Some brief comments on the correspondence principle are included. | |

... | Return to the top of this page. ... OR ... Return to physics.gpclements.com |

Photoelectric Effect, Quantum Mechanics | ||

Quantum Mechanics, Blackbody, Photoelectric Effect, Photon Energy, Momentum | Lecture (33 minutes) This video discusses the beginnings of quantum mechanics. The blackbody spectrum was not matched by the equations of Classical Physics. Planck assumed quantized oscillators were present and was able to derive a formula that matched the characteristics of the blackbody spectrum. The video discusses the photoelectric effect and how Classical Physics could not explain the observations of this effect. The video describes Einstein's photon model for light. The video discusses energy of photons. The video discusses evidence that photons have momentum and some uses for that effect. OpenStax College Physics. | |

Blackbody example, peak wavelength, compare power radiated by two blackbodies | Example (6 minutes) This video shows how to calculate the wavelength of the peak in the spectrum for a blackbody. The element used to make the blackbody does not affect the characteristics of the spectrum. The video also shows how to compare the power (or energy) emitted for two blackbodies. | |

Photoelectric Effect, Threshold, KE of ejected electron | Example (9 minutes) This video shows how to calculate the binding energy (work function) for a metal in the photoelectric effect. The video shows how to calculate the KE of the ejected electron. The video shows how to decide if a certain wavelength of light will cause an electron to be ejected. | |

Particle-Wave Duality, deBroglie Waves, Heisenberg Uncertainty Principle | Lecture (15 minutes) This video discusses the dual nature of light and objects. When light or objects are traveling between locations they act as a wave (show interference and diffraction effects). When they are emitted or absorbed they are best described as being localized. The method used to calculate the wavelength of an object is discussed. The Heisenberg Uncertainty Principles for position and momentum, and energy and time, are discussed. | |

deBroglie Wavelength Calculation for a Baseball and an Electron | Example (5 minutes) This video shows how to calculate the deBroglie wavelength for objects of a given mass and moving at a given speed. | |

Heisenberg Uncertainy Principle Examples | Example (7 minutes) This video shows how to calculate the uncertainty in the position of an electron that has a given uncertainty in its velocity. The video also shows how to calculate the uncertainty in the energy of an electron that has a given lifetime in an energy state. | |

... | Return to the top of this page. ... OR ... Return to physics.gpclements.com |

Atom, Pauli exclusion Principle | ||

Atoms, Brownian Motion, Rutherford Scattering Experiment | Lecture (14 minutes) This video describes the cause of Brownian motion. The video also briefly discusses the detection of electrons. The video discusses Rutherford's Scattering experiment that determined the atom has a small positively charged nucleus. Chapter 30 of OpenStax College Physics. | |

Bohr Model of the Atom | Lecture (18 minutes) This video discusses emission and absorption spectra, the Balmer series and Balmer's empirical formula for calculating wavelength, the Rydberg formula, the Bohr model for the atom, emission and absorption of light for the hydrogen atom, and Bohr's postulates of stable electron orbits and quantization of angular momentum. | |

Characteristic X-rays, Fluorescence & Phosphorescence, Lasers, Holography | Lecture (24 minutes) Topics: X-rays from electron transitions in atoms that have many protons, 2) Fluorescence, 3) Phosphorescence, 4) Lasers, 5) Holography. | |

Alpha Partcle "Colliding" with a Nucleus | Example (9 minutes) Topics: Calculate the distance of an alpha particle, with a given KE, to a nucleus of Nickel in a head-on collision. Calculate the KE of an alpha particle that starts at a given distance from the center of a copper nucleus. | |

Calculating Wavelength for Hydrogen Spectral Lines | Example (10 minutes) This video shows how to calculate the wavelength of the second Balmer line of Hydrogen using 1) Balmer's Formula, 2) Rydberg's Formula, 3) Energy Levels in Bohr's model of the Hydrogen atom. | |

Quantum Numbers for Electrons in an Atom | Example (9 minutes) This video shows how to write out the possible combinations of the angular momentum quantum number, the magnetic quantum number and the spin quantum number for electrons in an atom. The video also shows how to determine the maximum number of electrons in n=1 or n=2, and l=0 or l=1 states. | |

Electron Configurations for Fluorine, Neon, Sodium | Example (10 minutes) This video shows the procedure for writing the electron configuration for elements near the beginning of the periodic table. The video discusses why Fluorine and Sodium are very reactive but Neon is not reactive. | |

Radii of Electron "orbits" in Bohr's Model of Hydrogen Atom | Example (5 minutes) This video shows how to calculate the radii of the "orbits" of the electron for Bohr's model of the hydrogen atom. The electron actually does not have a definite orbit but this calculation gives you some feel for the Bohr model. Quantum Mechanics tells us that we should visualize a probability cloud for the electron in an atom, not a definite position. This material relates to Chapter 30 of OpenStax College Physics. | |

Atom Electron Wave, Zeeman Effect, Quantum Numbers, Pauli Exclusion | Lecture (29 minutes) This video discusses transition from the Bohr model of the atom to the Quantum Mechanical view of the atom. Topics: The relation of electron wavelength to circumference of Bohr orbits, Zeeman Effect, Quantization of Angular Momentum and the direction of Angular Momentum, "Spin" of Electron, Quantum Numbers, Pauli Exclusion Principle, Electron Configuration Notation, Periodic Table. This material relates to sections 6 - 9 of OpenStax College Physics. You should read the textbook before watching this video. | |

... | Return to the top of this page. ... OR ... Return to physics.gpclements.com |

Radioactivity, Half Life, Binding Energy | ||

Radioactivity Alpha Beta Gamma, Shielding, Detectors | Lecture (21 minutes) This video discusses the discovery of radioactivity and alpha, beta, gamma radiations. Shielding of these radiations is discussed. The Geiger Tube detector is discussed. | |

Structure of Nucleus, Isotopes, Alpha Beta Gamma Decay | Lecture (26 minutes) Topics: proton, neutron, notation for nuclei, conservation laws for nuclear reactions, radius of nucleus, stable nuclei, strong nuclear force, alpha, beta and gamma decay. | |

Radioactive Half Life, Activity, Binding Energy, Alpha Decay (Tunneling) | Lecture (24 minutes) Topics: Radioactive Half-Life, Activity, Total Binding Energy, Binding Energy per Nucleon, Alpha Decay, Quantum Mechanical Tunneling. | |

Balancing Nuclear Equations, Alpha, Beta, Gamma Decay | Example (6 minutes) This video describes how to determine the values for Z (charge units), A (count of protons and neutrons) and element name for alpha, beta, and gamma decay. | |

Decide if Proposed Alpha and Beta Decays are Spontaneous | Example (9 minutes) This video shows how to determine if an alpha or beta decay can occur spontaneously. If the mass of the original nucleus is larger than the total mass of the products of the decay the decay can occur spontaneously (without manipulating the parent nucleus) | |

Nucleus of an Atom, Radius and Density | Example (8 minutes) This video shows how to calculate the radius and density of Radon-222. We use the assumption that the nucleus is a sphere. The video also shows how to calculate the diameter of an object that has the mass of the Earth but the density of the nucleus. | |

Radioactivity, Activity and Half-Life Calculation | Example (10 minutes) This video shows how to calculate the activity number in Curies. The video also calculates the time elapsed for the mass of the sample of radioactive isotope to decrease to a specified value. We assume no nuclei escape or enter the container. | |

Initial Activity and Mass of Source Needed to Give Given Activity after Time | Example (12 minutes) The initial activity and mass of a radioactive source are calculated given the half-life, and desired activity after a set time. The initial activity is calculated from the exponential decay equation. The number of nuclei is calculated from the relationship between activity, the decay constant, and the number of nuclei. The mass is calculated using Avagadro's Number and the number of grams per mole for the isotope. | |

Total Binding Energy of a Nucleus and Binding Energy per Nucleon | Example (7 minutes) Topics: Calculate the total binding energy for Radon-222. The technique is to compare the total mass of the separated protons and neutrons to the mass of the original neutral atom. The electrons in the original atom are accounted for by using the mass of a neutral hydrogen atom when accounting for the proton mass. | |

... | Return to the top of this page. ... OR ... Return to physics.gpclements.com |

Dose, Fusion, Fission, TMI | ||

Radiation: Medical Use Imaging, Tracers, Hazards, Dose | Lecture (16 minutes) Topics; Radioactive Tracers, PET Imaging, Ionizing Radiation, Dose, Rad, Rem, Gray, Sievert, Safety. Chapter 32 of OpenStax College Physics. | |

Fusion of Hydrogen to Helium | Lecture (20 minutes) This video discusses why energy is released in fusion and fission. The video discusses the basics of fusion and why astronomers believe the source of the Sun's energy is fusion of hydrogen to helium. | |

Nuclear Power, Fission, Nuclear Plant Design, Atomic and Hydrogen Bombs | Lecture (15 minutes) Topics: Fission of Uranium, Chain Reaction, Atomic and Hydrogen bombs, Nuclear Power Plant Design. | |

Nuclear Power Plant Accidents: Three Mile Island, Chernobyl, Fukushima | Lecture (21 minutes) Topcs: Nuclear Power Plant Accidents: Three Mile Island, Chernobyl, Fukushima. Most of the video focuses on Three Mile Island. I started teaching in 1978 at Dickinson College, in Carlisle, PA. This location is about 20 miles from Three Mile Island. Our college had two Spring Breaks in 1979...one for the regular spring break and one week of closure due to the incident at Three Mile Island. | |

Radiation Dose Due to C-14 in an Office Desk | Example (11 minutes) This video calculates the absorbed and effective dose for a 70 kg person who sits in front of a wooden desk that naturally contains C-14. I make several assumptions that may or may not be true but the method of doing the calculation is OK. | |

Radiation Dose, Total and Effective | Example (7 minutes) This video calculates the total and effective dose for the case where a hypothetical radioactive source is swallowed by a 65kg person. | |

Fusion and Mass Loss for the Sun | Example (8 minutes) Topics: Number of fusions per second in the Sun, Annual mass loss for Sun due to fusion, Mass loss during 5 billion years, Comparison of mass loss for 5 billion years to current mass of the Sun. | |

Fission, Amount of U-235 Needed to Supply Small City for 1 Year | Example (9 minutes) Topics: Fission, Mass of U-235 needed to supply energy needs for 8000 homes if each home uses 11,000 kwH of energy per year. I assume 25% of the energy produced by the fissions reaches the customers. This calculation does not include energy needed by industry and business. | |

... | Return to the top of this page. ... OR ... Return to physics.gpclements.com |