Unit4_LeeJ

Unit4: Electricity and magnetismtoc

=Section 1: Static Electricity=

Lesson 1: Basic Terminology and Concepts & Lesson 2: Methods of Charging & Lesson 3: Electric Force & Lesson 4: Electric Fields
//Questions// //1. What is polarization?// //2. How can you charge an object?// //3. What is Electric Force?// //4. What is Coulomb's Law?// //5. What is Electric Fields?//
 * //__Summary__//**
 * Basic Terminology**
 * All matters are composed of atoms
 * J.J Tomson discovered the electron in the atom
 * Rutherford discovered the nucleus of the atom with Gold foil experiement. Also he thought the atom is mostly empty space
 * Bohr thought that electrons are orbitting around the nucleus in circular form(concept of electron shell)
 * Atom is combination of neutron, proton and electron
 * Proton is positive charged particle that is located in the nucleus
 * Neutron is neutral charged particle that is located in the nucleus
 * Proton and Neutron both are massive and tightly bounded
 * Electron is negative charged particle that is located in the outside of nucleus
 * It is weekly bounded and not massive as proton or neutron
 * It is charged because of difference of electron and proton
 * The unit of charge is Coulomb.
 * Same type of charged matters will repel each other and opposite type of charged matters will attract each other
 * Neutral objects will always attracted by any charged objects
 * Conductor is a material that allow the electron to flow.
 * Insulator is a material that doesn't allow the electron to flow
 * Superconductor means the best conductor that allows the electron to flow freely
 * Protons are not capable to moving
 * [[image:electricity_attraction.jpg]]
 * Polarization**
 * polarization is the process to seperate the charges in the object.
 * This process is able to occur due to the inducing electrons
 * It uses another charged object to induce electrons
 * Polarization also can happen in insulators
 * Bonds that one atom took the electrons of the other atom is called polar band
 * The biggest misconception of the polarization is that polarization is charging the matter, which doesn't happen at all.
 * Polarization is not charging
 * [[image:polarization.jpg]]
 * Methods of Charging**
 * Electron affinity is the property that is related how big is the desire of substance with eletron
 * By Friction
 * Rubbing process
 * The substances ordered by electron affinity is called triboelectric series.
 * Due to charging happens by transfering of electrons of 2 neutral matters, the net charge is 0
 * Total amount of charge of before process and after process are same and this is known as the law of conservation charge
 * [[image:Charged_by_friction.jpg]]
 * By Induction
 * Charge without touching
 * Charged object has no transfer of electron
 * It uses the charged object to induct the electron
 * When you use positive charged object, the electron will move toward the object and when you seperate 2 matters after electron induction, the matter near the positive charged object will charged negative and the matter away from the positive charged object will charged positive.
 * When you use negative charged object, the electron will move away from the object and when you seperate 2 matters after electron induction, the matter near the negative charged object will charged positive and the matter away from the negative charged object will charged negative.[[image:Charged_by_induction.jpg]]
 * The law of conservation of charge can observed
 * Ground means the great source of electron such as human body
 * When the ground touch the negative part of polarized object using negatively charged object, the electron will absorbed to the ground
 * When the ground touch the positive part of polarized object using positive charged object, the electron will given to the polarized object and charge it[[image:single_induct_of_electron_using_ground_charge.jpg]]
 * The common Lab demonstration of induction charge is electrophorus lab and electroscope lab
 * Electroscope is device that detects the charge
 * There are two common types of electroscope: gold leaf electroscope and needle electroscope
 * In the induction charge lab, needle electroscope is using
 * Both lab uses ground
 * [[image:electroscope_lab.jpg]]
 * [[image:Electrophorus_lab.jpg]]
 * By Conduction
 * Charged conductor contacts with neutral conductor to transfer the electron
 * When the negatively chaged conductor touched the neutral conductor, the electron on the charged conductor will transfer to the neutral conductor to charge it negatively.
 * When the positively chaged conductor touched the neutral conductor, the electron on the neutral conductor will transfer to the charged conductor and charge the neutral onductor positively.
 * The Law of Conservation of Charge observed
 * described with lightning
 * [[image:conduction_charge.jpg]]
 * Removal of Charge
 * removal process is called grounding because the exess charge will balanced when the ground touch the charged object
 * It can also happen through the conduction between the groun and charged object
 * If the ground touch negative charged object, the electron will transfer into the ground to balance the object
 * If the ground touch positive charged object, the electron will transfer into the object from the ground to balance the object
 * [[image:removing_the_charge.jpg]]
 * Electric Force**
 * Electric force is force that occurs by charged objects or polarized objects such as attractions and repel
 * If the force difference between oppostie forces are 0, the situation is at equilibrium
 * The sterngth of electric force can be described with vector quantity.
 * Coulomb's Law is the effects of three variable on electric force: F = (k)*(Q1)*(Q2) / (d ^2)
 * Q1 represents charge of object 1, Q2 represents charge of object 2, d represents distace between the objects and k represents coulomb's law constant: 9.0 E 9 (Nm^2) / C^2
 * Coulomb's law is similar to the gravitational force law
 * The charge of object is directly related with electric force
 * The distance between objects and electric force has inverse square relationship
 * Like the other forces, you can use the newton's law of motion.
 * There are lots of problems that includes vector addition and newton's law of motion, however, the process of solving it is same as before
 * [[image:sample_problem_of_electric_force.jpg]]
 * Electric Field**
 * It is common that electric makes the action at distance
 * Field force proved by the phenomenon that are happening without any contacts.
 * charges can attract and repel even they charged objects are far away from each
 * Chaged object creates the electric field that the region surround it
 * One most common example is Van de Graaff generator.
 * Due to great charge of van de graaff generator, bigger electric field will formed
 * Electric field strength is vector quantity
 * Electric field strength = Force / Charge
 * Electric field strength = k * Q * q / d^2 / q.
 * k represents the constant, Q represents source charge, q represents test charge, and d represent the distance between source charge and test charge
 * Simple form: k* Q / d^2. (q cancels out)
 * The electric field strength is directly related with source charge and inverse squarely related with distance.
 * The direction is determined that the whether the positive test charge is pulled or pushed
 * Electric field line represents the infinite vectors that surround the source charge
 * Negative: directed to source charge, positive: opposite direction of source charge
 * More line means more strength
 * The diagram can be exist with more than 1 source charge.
 * The vectors never intercept
 * Lots of pattern exist
 * Vectors move from positive charge to negative charge
 * All lines are perpendicular to the surface of the source
 * [[image:electric_field_line.jpg]]
 * [[image:sharp_point_electric_field.jpg]]
 * The middle space of charged conductor has 0 value of electric field.
 * It is shielded by faraday's cage and it shields ANY thing that will damage or affect to electric field.
 * When the surface has more curve of sharp, the dense of electric field(strong) of the surface is greater than other.
 * Lightning**
 * Strikes because of polarization in strom cloud
 * Type of frictional charging
 * Plasma occurs when the free electrons from the cloud insulate the air
 * It hits the highest upward positive charge, which called streamer, object first
 * lightning rod can protect from lightning because electric field is great in pointed surface
 * Lightning disspation theory: lightning rod will protect the houses from lightning by preventing lightning (wrong)
 * Lightning diversion theory: lightning rod will protect the houses from lightning by giving conductor path way to the Earth.

[] This shows the similar relation between the water flowing system and electric circuit.
 * The interesting appelt about relationship between water flow and electric circuit**

= Section 2: Current Electricty =

// Questions // // 1.What is electric potential // // 2. What is electric potential difference? // // 3. What is formula of power of electric energy that is supplied to the circuit or consumed by loads? // // 4. What is current? // // 5. What are requirements to have closed circuit? //
 * //__ Summary __//**
 * Electric potential **
 * Electric potential energy is simmilar with gravitational potential energy
 * Electric potential energy increase when work is needed, such as when you tries to locate same charged particles closer or different charged particles farther
 * Greater charge requires greater energy.
 * PE per charge( E = PE / Q)
 * Electric potential represents how electric field of source affect to the location that is in the electric field
 * Electric potential difference is difference between final electric potential and initial electric potential. The symbol is (delta)V
 * (delta)V = (delta)PE / charge
 * Electric potential difference also refer as voltage
 * It have unit of J /C
 * Electric pressure is also refers the voltage and electric potential


 * Battary power is the work done from positive end to negative end(actually the opposite way around)
 * Battary is only working as pump
 * Internal circuit represents the supply of energy to charge such as electrochemical cells in battary.
 * External circuit represents the object that the charge is outside of cells and travels through wire from high to low pressure
 * When electric potential is lossing during the circuit, the situation is called voltage drop
 * [[image:Electric_potential_energy.jpg]]

Common misconception is that battary is not rechargeble Some rechargeble battery is actually just doing reversible chemical reaction
 * Circuit **
 * Electric circuit is the closed loops of pathway that charges can continuously moving.
 * Always flow from high potential to low potential
 * To make a closed circuit, you have to connect the negative ene, which has low potential and positive end, which has high potential, and external circuit together. And make sure there is no opennings in your circuits
 * Only conductors are able to carry charges therefore if there is an object that is an insulator in your circuit, that is not a closed circuit it is opened circuit
 * The most common circuit is the circuit that is connected the battary and light bulb to check it is closed circuit or not.
 * However, if filament is burned or broken, the light bulb will not lit up
 * Potential difference will cause the flow of charges
 * The light bulb has special characteristic that will affact to the circuit. The special characteristic of light bulb is when the charge go into the tip of the bulb the charge always come out to ribbed side after it lit up the light or other way around.
 * [[image:Light_bulb.jpg]]
 * Current**
 * Current refers rate of charges that flows through the circuit
 * Current = I = Q / t
 * Q refers charge(coulomb) t refers time(second)
 * Unit of current: ampere.
 * 1 ampere = 1coulomb / 1 second
 * The direction of electric current is depend on the direction of positive charge
 * Drift speed represents the average distance that charged particle carrier moved
 * The difference between drift speed and electric current is that drift speed is chaotic
 * Also the drift speed is extremely slow
 * [[image:difference_between_drift_speed_and_electric_current.jpg]]
 * Power**
 * The power is the rate of electrical energy
 * The concept of power is same as previous we learned.
 * Load is energy consumer such as light bulb.
 * Power = work done on charge / time = Energy consumed by load / time
 * The unit is Watts
 * To calculate power, you can combine 3 equations to make more simple.
 * P = E / t, I = Q / t , V = PE / Q
 * E = V * Q therefore P = V * Q / t
 * Q = I * t therefore P = V * I

Lesson3: Electrical Resistance & Lesson 4: Circuit Connection
//1. What is ohm's law?// //2. What is electrical resistance?// //3. What is series circuit?// //4. What is parallel circuit?// //5. What is Combination circuit?//
 * //__Summary__//**


 * Resistance**
 * Resistance is the material's ability to interrupt the flow of charge
 * If material is closer to conductor, it has lower resistance and if the material is closer to insulator, it has higher resistance
 * It decreases rate of flow and drift speed of electron
 * It has direct relationship with resistivity, length and inversely with cross sectional area of wire the charge travels
 * Resistance is also affacted by the type of material
 * Resistivity is the conducting ability that depends on temperature and electronic strcture
 * Lower resistivity means lower resistance and higher conductor
 * The unit of resistance is Ohm, greek letter omega.
 * Due to the relationship with area, length, and resistivity, the mathematical formula of resistance is R = p*L / A
 * p represents resistivity, L represents Length, A represents cross sectional area
 * Ohms Law**
 * V = I * R
 * where V represents Voltage, I represents current, and R represents resistance
 * It also can rewrited as I = V / R
 * Which means current is directly related with voltage and inversely related with resistance
 * P = V * I therefore P = (I^2) / R and P = (V^2) / R
 * [[image:정리.jpg]]
 * Circuit diagram**
 * Circuit can be described as word and image. To simpliy the real image, you can draw the circuit diagram by using circuit symbols
 * For the battery and single cell, the longer line refers the positive terminal
 * [[image:Circuit_symbol.jpg]]
 * [[image:circuit_diagram.jpg]]
 * Series Circuit**
 * In series circuit, the resistors such as bulbs are connected with same line of wire
 * If there is more resistors, the current will decrease. For example, the light bulb will decrease its brightness when you add more bulbs
 * If you disconnect one resistor everything will turned off by creating opennings.
 * When you add more resistor, it refers that overall resistance became greater
 * Only one pathway exist
 * Equivalent resistance is the amount single resistor needed to equal the effect of the resistors in circuit
 * Equivalent resistance is the sum of resistance of each resistors in series circuit
 * Current is same at everywhere
 * Calculated by ohms law
 * Voltage increases by adding the batteries and decrease by resistors and to calculate them, just use + or - to get net value for each section
 * When you calculate the current, you should use the voltage of battery and equivalent resistance
 * When you calculate the voltage of each section, you should use the current and each resistance of resistor that will affect to the section V1 = I * R1
 * [[image:series_connection.jpg]]
 * Parallel Circuit**
 * In parallel circuit, the resistors such as bulbs are connected with multiple pathways called branches**.**
 * It requires the indicator bulb that is out of branch to observe the affect of adding resistors.
 * Increase of resistors will increase overall current and decrease overall resistance
 * Even though you took one bulb out of the branch, the remained bulbs will still lit up
 * Current will be same but when it go in to the branches, it separates as many as branch is and the braches may have different current. However the total current is always same. Sum of the current of each branch will equal to the current of outside of branch
 * Equivalent resistance is the amount single resistor needed to equal the effect of the resistors in circuit
 * (1/equivalent resistance) = (1/resistance of resistor 1) + (1/resistance of resistor 2).....
 * Voltage of the parallel circuit is always equal to the voltage that have been left when it come to the path of branch
 * When you calculate the current of each branch, you should use the voltage of battery and each resistance of resistor that will affect to the branch I1 = V / R1
 * The least resistance resistor have greatest current which means that the charges choose the pathway that has least resistance
 * [[image:Parallel_connection.jpg]]
 * [[image:Total_current_of_parallel_circuit.jpg]]
 * Combination Circuits**
 * Combination circuit is the circuit that includes both parallel circuit and series circuit.
 * The properties are same just combined
 * Make sure to not confuse
 * [[image:sample_calculation_of_combined_circuit.jpg]]

Answers: //1. What is ohm's law?// Ohms law stated the relationship between resistance, votage and current and the equation can predict the values of them. Equation: V = R * I //2. What is electrical resistance?// electrical resistance is the ability of object the hinder or pause the charge //3. What is series circuit?// Series circuit is circuit that is connected with one path //4. What is parallel circuit?// Parallel circuit is circuit that is connected with multiple path //5. What is Combination circuit?// Combination circuit is circuit that involves both series circuit and parallel circuit

LABS: Ohm's law Objective: What is the relationship between pressure difference and flow rate in investigation 1? Objective2: What is the relationship between pressure difference and flow rate in investigation 2?

Hypothesis1: in the investigation 1, relationship between pressure difference and flow rate will be directly proportional Hypothesis2: in the investigation 2, relationship between pressure difference and flow rate will be directly proportional

DATA ' Calculation
 * R = V / I, sample: 1 / 0.001 = 1000
 * % error = (abs(actual - theoratical) / theoratical) * 100 Theoratical is decoded value of resistor.
 * sample: (abs(695 - 1000) / 1000) * 100 = 30.5 %

Analysis Questions
 * Graph of investigation 1 was linear and had direct relationship.The slope of the graph of investigation 1 is the resistance of the resistors. In equations y = 695x and y = 1761.9x, y represents voltage, x represents current and slope represents resistance. This is fit to the ohms law and therefore the resistor used in investigation 1 is ohmic material. Ohmic material is the material that follow ohms law. For the investigation 2, we used light bulb as resistor and the graph was not a linear. It was the power graph and which means when voltage was added, the resistance increased. This is not fit to ohm's law and should not happen, therefore the light bulb is non ohmic material. Non ohmic material is materials that does not follow ohms law.

[] This diagram and explanation explains what field line is and shows it.
 * The interesting animation about electric field**