## General Physics II...YouTube Videos: Electricity, Magnetism, Optics, Relativity, Atom, Nucleus

[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