Physics - Chapter 22 Electrostatics

Electric Field - Electric shielding 1. The test charge at P is ??? just as much to the greater amount of ??? at farther region A as it is to the ??? amount of charge at closer region B. 2. The net force on the test charge is ??? - there, or anywhere inside the ???. The ??? field everywhere inside is also zero. 3. Complete ??? occurs at all points within the sphere, just like how gravity would be cancelled out in the theoretical ???

1. attracted, charge, smaller 2. zero, conductor, electric 3. cancellation, hollow planet

Electrostatics 1. The enormous ??? and repulsive electrical forces between the charges in Earth and the charges in your body ??? ???, leaving the relatively weaker force of ???, which only ???. 2. -- Each body of mass is relatively ??? in terms of its charge.

1. attractive, balance out, gravity, attracts 2. neutral

Electric Field - Electric shielding Why we are safe from lightning strikes while inside of our vehicles?

*As a lightning bolt strikes a car, the electrons are conducted along the metal surface of the car. *The electrons will mutually repel each other, and the electric field on the outside of the car will be great, but the net electric field inside the car is zero. *The charge will be carried to the ground either through the tires or via discharge to the ground.

Electric Field Electric field configurations can be useful to us for visualizing a 3-D scenario working in a 2-D model. *We can use field lines to represent a small number of the ??? numerous possible lines that indicate the ??? of the field. *Where the lines are ??? apart, the field is ???

*infinitely, direction *farther, weaker.

Electric Potential The concept of electric potential energy per unit charge has a special name: 1. ? We can measure this as: 2? Consider this: for 2 charged bodies near the same charged object, one body has 10C of charge at a specific location and 10 times as much EPE as an object with 1C of charge 3. What is the same and what is different

1. Electric Potential 2. Electric potential energy (in joules)/charge (in coulombs) 3. Same: Different

Coulomb's Law 1. One special difference to note is that electric forces can be ??? or ???, unlike gravitational forces which are only ??? The SI unit of charge is the coulomb, abbreviated C. -- A charge of 1C is the charge of ??? electrons. -- A coulomb represents the amount of charge that passes through a common 100-W light bulb in about ??? second.

1. attractive, repulsive, attractive. --6.24 x 1018 --one

Conductors and Insulators 1. In power lines, charge flows much more ??? through hundreds of kilometers of metal wire than through the few centimeters of ??? material that ??? the wire from the support tower. *Charge will take the path of least ???

1. easily, insulating, separates *resistance!

Conductors and Insulators 1. Conductors have ??? resistance to the flow of ??? charge, while insulators have a much ??? resistance to electric charge. 1*Some materials can be remarkably ??? at one or the other. 2. Interesting progress has been made with ??? - materials that acquire nearly ??? resistance to the flow of charge. Once the charge is established, the electrons will flow ??? 2*Zero resistance means that ??? ??? is lost from point A to point B.

1. little, electric, greater 1*good 2. superconductors, zero, indefinitely. 2*no energy

Electrostatics - Quick Chemistry Review... 1. We conventionally say that electrons are ??? charged while ??? are positively charged. 2. Let's not forget neutrons, which have ??? charge as they are not attracted by nor repelled by ??? particles.

1. negatively, protons 2. no, charged

Charge Polarization - Electric Dipoles 1. Many molecules are electrically polarized in their ??? states. --In these cases the distribution of electric charge is not perfectly ??? --One atom in a molecule, of a functional group of a molecule, will get a little ??? ??? charge than the other side of the molecule. --This is due to --Such molecules are said to be 2. What is a great example of this?

1. normal --even --more negative --an unequal sharing of electrons in a chemical bond. --electric dipoles. 2. Water

Coulomb's Law 1.This is ??? always true at the ??? level! *Often two or more atoms, when close together, share ??? 2. Bonding = when the attractive force between the ??? of one atom and the positive ??? of another atom is ??? than the repulsive force between the ??? of both atoms. Bonding ??? leads to the formation of ???

1. not, atomic *electrons 2. electrons, nucleus, greater, electrons, molecules.

Conductors and Insulators 1. Outer electrons of the atoms in a metal are ??? anchored to the ??? of particular atoms, but are ??? to roam in the material. 1a. We would call this the ??? ??? ??? for those ??? metal atoms 1b. This is caused by the ??? ??? of the ??? ??? for the metal atoms, so each electron can move between orbitals at the same energy level 2.Materials through which electric charge can flow are called ??? 2a.The "???" electrons in metals make them ??? conductors

1. not, nuclei, free 1a. sea of electrons, bonded 1b. hybridized overlapping, outer orbitals 2. conductors. 2a. loose, good

Electrical Forces and Charges 1.When considering charge, we term it as being made up of elementary units called ??? 2. Charge would then be quantized, with the ??? quantum of charge being that of the ??? (???). a. So a quanta is a ??? or amount of something. b. Termed as such by ??? when observing the absorption or emission of electromagnetic radiation in photoelectric experimentations (~1900)

1. quanta. 2. smallest, electron, or proton a. measurement b. Max Planck

Electrical Forces and Charges Attraction and Repulsion 1. The fundamental rule is that like charges ??? while opposite charges 2. Just like directionality, positive and negative are just names given to opposite charges by ???

1. repel, attract.

Conductors and Insulators 1. Electrons in other materials - such as ??? or glass - are more ??? bound and ??? with particular atoms. *They are ??? free to wander about to other atoms in the material. 2. These materials, known as ???, are ??? conductors of electricity.

1. rubber, tightly, remain *not 2. INSULATORS, poor

Electric Field - Electric shielding 1. Since gravity only attracts, we cannot shield ourselves from gravity. Why? 2. How does one shield an electric field? 3. The ??? charges in the conducting surface will arrange themselves on the surface of the conductor in such a way that all field contributions ??? ??? one another. --This is why certain electronic components are encased in metal boxes and why certain cables have a metal covering - to shield them from outside ??? ???

1. there are no repelling parts to offset attracting parts. 2. simply surround an object with a conducting surface. 3. free, inside cancel --electrical activity.

Charging 1. Electrons are transferred from one material to another by simply ??? *This method of charging is called charging by ???. 2. When a ??? object is placed in contact with a neutral object, some charge with transfer to the ??? object. 3. If the object is a ??? ???, the charge will spread out to all parts of its surface because the ??? charges ??? each other.

1. touching. *contact 2. charged, neutral 3. good conductor, like, repel

Electric Potential 1. The unit of measurement for electric potential is the ???, so electric potential is called ???. 1 volt = 1 x joule/coulomb so... a 9 volt battery gives 1.5 joules of energy to every 1 coulomb of charge passing through the battery 2. The use of electric potential and voltage are ???, and either can be ???

1. volt, voltage 2. common, used.

Electrostatics Who is the master of electrostatics?

Nikola Tesla

Charging Lightning rods help us out with controlling where lightning strikes by induction take place.. --, who found that charge flows readily to or from sharp metal points? If a rod is placed above a building and connected to the ground, the point of the rod collects electrons from the air. --This prevents a buildup of positive charge by induction - almost like forming a barrier around a building.

Originally invented by Benjamin Franklin

Electrostatics Recall back to our chapter on gravity when we looked at our four fundamental forces. They ranked: 1. Strong nuclear forces 2. Electromagnetic forces 3. Weak nuclear forces Gravitational forces -- Compared to gravity, electrical forces are much, ??? ???

much stronger.

Electric Field Just like the space around a planet is filled with a gravitational force, the space around every electrically charged body is filled with an 1. ELECTRIC FIELD definition --Gravitational fields were represented with ??? ??? directing towards the ??? of mass of the body exerting gravitational force. 2. An electric field can have ??? and directionality (repel and ???) --The magnitude is just the ??? per unit of charge. If a body with charge q experiences a force F at a point in space, then the electric field E at that point is: E = F/q

1. an energetic aura that extends through space. --FIELD LINES, center 2. magnitude, attract --force

Electrostatics - Quick Chemistry Review... 1. We can trace these forces back to the ??? that make up all of ??? a.-- Electrical forces arise from ??? in atoms. 2. The ??? in the nucleus attract the ??? and hold them in ??? 3. Electrons are ??? to the protons, but ??? other electrons. 4. Each ??? particle, then, has a charge that corresponds to the mutual ??? ??? ???? observed.

1. atoms, matter a. particles 2. protons, electrons, orbit 3. attracted, repel 4. sub-atomic, attractions or repulsions

Electric Field 1. For gravitational field lines, the strength of the field was indicated by how ??? the field lines became to one another as they approached the ??? ??? ??? 2. For an electric field, we have another convention to follow to allow directionality (definition): *The "test charge" is *Thus, an electric field vector will always be shown to move ??? towards a negative charge and outward from a ??? charge.

1. closely, center of mass. 2. the direction of the field line vectors will move in the perspective direction of a small positive test charge. *a theoretical charge of such small value that it does not alter the electric field with which it interacts. It only follows its influence. *inward, positive

Conductors and Insulators 1.A substance can then be classified as a ??? or an insulator based on how ??? the atoms of the substance hold their ??? . 2.The conductivity of a metal can be trillions of times ??? than the conductivity of an ??? such as glass. *Materials that don't hold electrons tightly ??? them to materials that hold electrons more ???

1. conductor, tightly, electrons 2. greater, insulator *lose, tightly.

Electrostatics 1. Electrostatics - ??? a. Involves ??? ???, the ??? between them, the ??? around them, and their ??? in materials. b. An understanding of electricity requires a step-by-step approach, starting with ??? - then moving on to ???

1. definition: energy at rest a. electric charges, forces, aura, behavior b. statics, dynamics

Coulomb's Law 1. Newton's law of gravitation of masses is similar to Coulomb's law for ??? charges. 2. Whereas the ??? force of attraction between 1 kg masses is extremely ???, the electrical force between ??? of one coulomb charges is extremely ??? 3. The greatest difference between gravitational force and electrical force is that gravity only ??? but ??? forces may attract and ???

1. electric 2. gravitational, small, a pair, large 3. attracts, electrical, repel.

Electricity What is electricity? -- We may think of lightning that we see in the sky, or the power running through the wires to make our devices work. 1. Electricity is a broad name given to a wide range of ??? phenomena that underlie just about ??? around us. a. From ??? made when a match is struck to what holds ??? together b. ??? electricity is what allows us to use modern ???

1. electrical, everything a. sparks, atoms b. Controlling, technology

Electric Field 1. Just like gravitational forces, ??? forces act between things that are ??? ??? ??? with each other. *For both, a ??? ??? exists that influences ??? and massive bodies, respectively. From chapter 9, we saw that the properties of space surrounding any massive body are altered such that another massive body introduced to this region will experience a force. *With gravity, this is a gravitational field 2. An object can then be thought to interact with the ??? field, more so than the object that produces the field. *The field plays an ??? role in the force between bodies.

1. electrical, not in contact *force field, charged 2.force * intermediate

Charging 1.What happens when a negatively charged rod is held near one sphere? Excess negative charge has moved to the other sphere, leaving the first sphere with an excess positive charge. These electrons are able to move due to the spheres being in contact. 2.What has happened to the charge on the spheres?

1. electrons in the metal are repelled by the rod. Opposites repel, like charges attract 2. The charge has been redistributed or induced.

Coulomb's Law 1. Because most objects have almost exactly ??? numbers of electrons and protons, electrical forces usually ??? out. -- Between the earth and moon, for example, there is no measurable ??? force. 2. In general, the weak ??? force, which only attracts, is the predominant force between ??? bodies.

1. equal, balance --electrical 2. gravitational, astronomical

Charging 1. If you slide across a seat in an automobile, you are in danger of being charged by ??? 2. If you then touched another "object", that ??? charge may transfer by ???

1. friction. 2. gained, contact!

Electrical Forces and Charges Conservation of Charge 1. The ??? electrons in an atom are bound ??? to the ??? charged atomic ??? 2. The outermost electrons (???) are bound more ??? and can be easily ??? -- The amount of energy required to tear an electron away from an atom varies for different ???

1. innermost, tightly, oppositely, nucleus. 2. valence, loosely, dislodged. --substances.

Conductors and Insulators 1. Semiconductors are materials that can be made to behave sometimes as ??? and sometimes as conductors. 2. Atoms in a semiconductor hold their ??? until given small energy boosts. 2a.This occurs in the ??? cells that convert solar energy into ??? 2b. ??? can include germanium (Ge) and silicon (Si)

1. insulators 2. electrons 2a. photovoltaic, electricity. 2b. Examples

Conductors and Insulators 1. The first superconductors were discovered in ??? near absolute zero in ??? *Progress has been made since in this field, with superconductors that work at "???" temperatures, as well as ??? superconductors being found. 2. This applies in ??? power lines and in ???, magnetically ??? trains

1. metals, 1911. *high, non-metallic 2. low-loss, high-speed, levitated

Charge Polarization 1. The bits of paper experience a ??? 2. Sometimes they will cling to the charged object and suddenly "???" off. --Charging by ??? has occurred --The paper bits have acquired the ??? sign of charge as the ruler and are then ???

1. net attraction 2. fly --contact --same, repelled.

Electrical Forces and Charges 1. If an electron is removed from an atom, the atom is no longer ??? because it will now have more ??? charged particles than negative. a. A charged atom is called an ???, and can be positive or negative depending on whether it lost or gained electrons. 2. Why don't we consider atoms losing protons, just electrons? 3. Would they still be ions?

1. neutral, positive a. ion 2. because it is no longer neutral and it will now have more positive charges than negative ???????????? 3. yes. it is still a charged atom

Charging 1. When we touch the metal surface with a finger, charges that ??? each other have a conducting path to a practically infinite reservoir for an ??? charge - the ground. 2.What is it called when we allow charges to move off (or onto) a conductor by touching it? 3. When we encounter electricity, we will ??? ??? see that it wants to "go to ground" - travel a pathway towards the earth as it is a large source of charge! -- Who uses this knowledge?

1. repel, electric 2. we are grounding it 3. almost always ---Electricians

Conductors and Insulators 1. Thin layers of semiconducting materials sandwiched together make up ??? 2. ??? are used to control the flow of electrons in ???, to detect and amplify radio signals, and to produce ??? in transmitters.

1. transistors. 2. Transistors, circuits, oscillations

Charging 1. Does charging by induction occur during thunderstorms? Why or why not? 2. Most lightning is an electrical discharge between ??? charged parts of clouds.

1. yes because the negatively charged bottoms of clouds induce a positive charge on the surface of Earth below. 2. oppositely (The kind with which we are most familiar is the electrical discharge between clouds and oppositely charged ground below.)

Charge Polarization 1. Is charging by induction restricted only to conductors? Why or why not? 2. When a charged rod is brought near an insulator, are there free electrons to migrate throughout the insulating material? 3. Instead, there is a rearrangement of the positions of charges within the ??? ??? ??? themselves. 4. When one side of the atom or molecule is induced to be slightly more positive (or negative) than the opposite side the atom or molecule is said to be ???

1.No because charge polarization can occur in insulators that are near a charged object. 2. there are no free electrons to migrate throughout the insulating material. 3. atoms and molecules 4. electrically polarized.

Electric Field - Electric shielding The metallic casing of the microwave will internally reflect the waves generated, to make the cooking more rapid and efficient. The use of materials that do not contain water or polar molecules are recommended for use in the microwave as the waves will pass through them with no effect. *Why are we told to not put metal into the microwave? -- Would microwaving be an efficient way of melting ice?

*since metal doesn't contain any water, it has no way to effectively use those microwaves and metal is bad at absorbing water. --ice water molecules are locked together by quite strong hydrogen bonds, and to melt it has to break a lot of these bonds, which takes a lot of energy.

Electric Field - Electric shielding -- We can relate this to a ??? - invented by scientist Michael Faraday in ??? Faraday learned that electromagnetic fields can be ??? by enclosing an object in a continuous ??? ??? ??? materials. This is what is responsible for the shielding in an MRI room, your loss of cell signal inside elevators or buildings, booster bags, and your safety from being cooked via your microwave oven! *And other fun applications - video...

--Faraday cage, 1836. blocked, covering of conductive

Charge Polarization - Electric Dipoles The oppositely charged ends of the molecule can then induce a similar charge in other molecules, or can experience an attractive/repulsive force from other charged molecules or dipoles. --It is due to this ??? structure that many things in chemistry can occur in an ??? solution (in a solution dissolved/dissociated in water). --This formation of electric dipoles is also what is responsible for the formation of ??? bonds - the electrical force of attraction that holds our ??? together!

--dipole, aqueous --hydrogen, DNA

Practice - Coulomb's Law 1. Two point charges are separated by 12cm. The attractive force between them is 45N. Supposing that the charges attracting each other are equal in magnitude, find the relative charges of each point charge present. 2. Given the following three scenarios, rank the magnitudes of the force between pairs of charges from largest to smallest. a.Two points with charges of +2μC and -4μC are located 8cm apart b.Two points with charges of +3μC and +3μC are located 8cm apart c.Two points with charges of +2μC and -2μC are located 4cm apart

1. 2a. 2b. 2c.

Charge Polarization A: To summarize, objects are electrically charged in three ways: B.If the object is an insulator, then a ??? of charge rather than a ??? of charge occurs, on the other hand. --This is charge ??? , in which the surface near the charged object becomes ??? charged.

1. By friction, when electrons are transferred by friction from one object to another. 2. By contact, when electrons are transferred from one object to another by direct contact without rubbing. 3. By induction, when electrons are caused to gather or disperse by the presence of nearby charge without physical contact. B. realignment, migration -- polarization, oppositely

Charging By friction and contact - We are familiar with instances where static electricity can build up and transfer between objects or materials. *When petting your family animal (assuming it has hair), you can hear the crackle of sparks that are produced. *Taking your jacket off in front of a mirror in a dark room, you can see and hear the sparks of electricity. 1. ??? are being transferred by ??? when one material rubs against another.

1. Electrons, friction

Charging 1. What is the primary purpose of the lightning rod? 2. What does a lightning rod prevent?

1. To prevent a lightning discharge from occurring. If lightning does strike, it may be attracted to the rod and short-circuited to the ground along heavy-duty wires, sparing the building. 2. It prevents things like fires from starting due to lightning strike.

Charging Charging by Induction - Inducted charging can be illustrated using two insulated metal spheres. 1. ??? insulated metal spheres touching each other, in effect, form a single non-charged ??? --If a charge were applied to one sphere, the charge can be ??? along the surface of one sphere to the ???

1. Uncharged, conductor --carried, other.

Charge Polarization A - When an external negative charge is brought closer from the left, the charges within a neutral atom or molecule ??? B - All the atoms or molecules near the surface of the insulator become ???

A. rearrange. B. electrically polarized.

Coulomb's Law Of what significance is it that G in Newton's law of gravitation is a small number (10-11) and k in Coulomb's law is a large number?

Basically, the reason that Coulomb's constant is so much larger than the gravitational constant is that gravitational force is much weaker than other fundamental forces, including electrostatic force.

Prompt card Charge Polarization To summarize, objects are electrically charged in three ways: By friction, when electrons are transferred by friction from one object to another. By contact, when electrons are transferred from one object to another by direct contact without rubbing. By induction, when electrons are caused to gather or disperse by the presence of nearby charge without physical contact. If the object is an insulator, then a realignment of charge rather than a migration of charge occurs, on the other hand. This is charge polarization, in which the surface near the charged object becomes oppositely charged.

Coulomb's Law 1. Two point charges are separated by 12cm. The attractive force between them is 45N. Supposing that the charges attracting each other are equal in magnitude, find the relative charges of each point charge present. 2. Given the following three scenarios, rank the magnitudes of the force between pairs of charges from largest to smallest. a.Two points with charges of +2μC and -4μC are located 8cm apart b.Two points with charges of +3μC and +3μC are located 8cm apart c.Two points with charges of +2μC and -2μC are located 4cm apart

Electrical Charges and Forces Similar to our other conservation principles (momentum, energy), we can examine the CONSERVATION OF CHARGE. Def: This states that whenever something is ???, "no electrons are created or ???, but are simply ??? from one material to another." 1. This applies at the large scale or at the ??? or ??? level! a. An application of this is that electrons ??? be divided into ??? of electrons, so the charge of an object is a ??? multiple of the charge of an ???

Def: charged, destroyed, transferred 1. atomic, nuclear a. cannot, fractions, whole-number, electron

Coulomb's Law We can use the equation:

F = K x (q1xq2)/d^2 d is the distance between charged particles q1 represents the quantity of charge of one particle q2 is the quantity of charge of the other particle k is the proportionality constant (similar to the gravitational constant, G)

Charge Polarization Example: Rub an inflated balloon on your hair and it becomes charged. What happens when the balloon is placed against the wall?

If all goes well, the charge on the balloon induces an opposite surface charge on the wall. --The charge on the balloon is slightly closer to the opposite induced charge than to the charge of the same sign.

Charging Have you ever seen those signs at the gas station pump, saying to not go back into your car while pumping gas? Why is this?

If we get back into and out of your car, you could gain an electric charge by friction. The danger would be to transferring that charge to the gas pump handle/nozzle while the highly combustible, volatile gasoline is being pumped out in great volumes. Keep an eye out for discharge pads on gas pumps to help. Or, simply, touch a grounded metal surface to discharge yourself safely.

Electrical Forces and Charges Fun other thoughts to consider: Why don't positively charged protons in the nucleus mutually repel each other and fly apart? What holds the nucleus together?

Somewhat due to electrical forces, but much more so to the strong nuclear forces present, holding protons together with stronger force than the electrical repulsion.

Charge Polarization Example: Let's take a plastic ruler and bits of paper. Both are (should) be neutrally charged. A negative charge can be induced onto the plastic ruler, by friction with another surface full with electrons. What happens to the molecules within the paper bits?

The molecules within the paper bits (thus the paper itself) can become polarized, with oppositely charged sides of molecules closest to the charged object.

Electrical Forces and Charges Fun other thoughts to consider: Why don't positively charged nuclei pull the negatively charged electrons into the nucleus?

This is where quantum mechanics was born as a response to this question in 1911! Electrons occupy space in at atom within designated orbitals or shells, depending on their energy level, that spreads the electrons out in a 3-D space. Electrons have a dual wave-particle nature suggesting that a shell is the required space needed related to its wavelength.

Electrical Forces and Charges What do you think is occuring (in physics terms) when you shuffle your feet along the carpet/rug when walking. Are you negatively or positively charged?

When done, you pick up electrons from the rug, becoming negatively charged (and the rug positively charged)

Electric Energy Storage Capacitors are found in nearly all electronic circuits (Definition). Examples: 1. Camera photoflash units - stored energy is quickly released in a flash of a short duration. 2. Defibrillator - short bursts of energy are applied to a heart attack victim. To function and to give a controlled shock, the defibrillator must charge up (put a charge into the capacitor) 3. Lasers! - large capacitor banks power giant lasers in national labs.

a controlled electrical pathway used to power electronic devices

Electric Field - Electric shielding About those microwaves which can cook so many things - how do they work? The machine does produce microwaves (definition) *The ??? casing of the microwave device shields you from the ???getting outside - and cooking you. *The electric field generated will interact with the ??? water molecules in the food, but not the ??? molecules. *When the field oscillates, the ??? molecules also oscillate - flipping back and forth - producing a lot of ??? friction and cooks your food *The H2O molecules flip at a rate of ??? ??? times per second! **For perspective, some estimations say that ??? live for ~2.45 billion seconds on avg

a form of electromagnetic radiation, that is oscillating in frequency. *metallic, radiation *dipole, non-polar *H2O, kinetic *2.45 billion **humans

Electrostatics - Quick Chemistry Review... Some quick atomic facts to recall: a. Every atoms has a positively charged ??? surrounded by negatively charged ??? b. All electrons are ??? c. The nucleus is composed of protons and ???. All protons are ???; all neutrons are ??? d. Atoms usually have as many electrons are ???, so the atom has ??? net charge (???) e. A proton has nearly 2000x the ??? of an electron but its positive charge is ??? in magnitude to the negative charge of the electron.

a. nucleus, electrons. b. identical c. neutrons, identical, identical. d. protons, zero, neutral e. mass, equal

Electrical Forces and Charges Let's make a connection now: If matter is made up of atoms, composed of electrons and protons, and these atoms can be ions based on the ??? of charges within those atoms. If the atoms are ??? charged, then the matter composed of those charged atoms will also be ??? charged.

balance electrically, electrically

Electric Field - Electric shielding Interestingly, complete ??? occurs anywhere inside a ??? sphere. Let's consider a test charge at point P inside the sphere. The test charge is twice as far from the left side as it is from the right. *If only ??? mattered, the test charge would be attracted only ??? as much to the left side as to the right. *We have to consider charge too, however, (Coulumb's Law) so, extending a 3D cone from the charge to either side of the sphere, we get areas A and B with the same ??? angle, but B has twice the ??? *The area of A at the base is ??? ??? than the area of B at the base. *Using the charge and distance, point P is attracted ??? to each side.

cancellation, conducting *distance, ¼ *apex, altitude. *4x larger *equally

Electric Field Electric fields can be observed using ??? materials suspended in ??? media - such as magnetic thread floating in oil. *The images should remind us of iron filings in a ??? field.

conductive, insulating *magnetic

Coulomb's Law Electrical force, like gravitational force, ??? inversely as the ??? of the distance between charged bodies. *This relationship was discovered by ??? in the ??? century. *This makes an electrical force similar to a ??? force, even in how they are ??? This relationship is expressed as ??? - for two charged objects that are much ??? than the distance between them, the ??? between the two objects varies ??? as the product of their charges and ??? as the ??? of the ??? distance.

decreases, square *Charles Coulomb, 18th *gravitational, calculated. Coulomb's Law, smaller, force, directly, inversely, square, separation

Charging What happens if the spheres are separated while the rod is still present?

each sphere will be equally and oppositely charged. *They have been charged by induction, which is the charging of an object without direct contact.

Electric Field - Electric shielding Another difference between electric fields and gravitational fields is that of ??? *Electric fields can be shielded by various materials with the amount of ??? depending on the ??? used. Ex: Air makes the electric field between two charged objects slightly weaker than it would be in a vacuum, while oil placed between objects can dimmish the field to nearly 1/100 its original strength. What can completely shield an electric field?

electric shielding. *shielding, materials Metal

Electrostatics Consider a force acting on you that is billions of times stronger than gravity. Suppose that, in addition to this force, there is a repelling force, also billions of times stronger than gravity. If so, then the two forces should balance each other out with no noticeable effect. -Such a force exists and it is called: ??? ???

electrical forces

Electrostatics - Quick Chemistry Review... As an example, let's look at a Bohr model for a helium atom. The nucleus has two protons and two neutrons. The two protons are attracting two negatively charged ???

electrons

Coulomb's Law The proportionality constant k in Coulomb's law is similar to G in Newton's law of ???, but with a different value. k = 9,000,000,000 N*m^2/C^2 or 9.0 x 10^9 N*m^2/C^2 If a pair of charges of 1C were 1m apart, the force of repulsion between the two charges would be ???

gravitation ???

Electric Potential We previously learned that, due to an objects position in a gravitational field, the object can have ??? ??? energy. *If an object is positioned away from the ??? ??? ??? or suspended above a support surface, it has potential energy related to its (3 items): PE = mgh Just as work is required to lift an object against the gravitational field of Earth, work is required to push a charged particle against the ??? ??? of a charged body. *This work changes the electric ??? ??? of the charged particle

gravitational potential *center of mass, 1. mass, 2.relative height, and 3.the accelerative forces of gravity. electric field *potential energy

Electric Field - Electric shielding How would this (electric shielding) work is our conductor was non-spherical? The charge distribution will ??? However, they will follow ???/??? charge interactions until ??? is reached, meaning: 1. The potential energy of mutual ??? of the charge on the surface of the object is at its ??? 2. The ??? charge distribution over the surface is such that the electric field inside the ??? is ???

not be uniform! mutual/opposite, equilibrium 1. repulsion, lowest. 2. exact, conductor, zero.

Electrical Forces and Charges But what about quarks!? a.Within the nucleus, the proton and nucleus are each made up of three quarks defined as: b. Quarks have always been found to exist in a charge ratio of ???within the ??? and ??? 1. These quarks are given the assignment of "???" quarks and "???" quarks 2. Protons have ??? up quarks and ??? down quark; neutrons have ??? up quark and ??? down quarks. 3. The ??? are fractions of the charge of an electron, so, combined together in the nuclear particle, they can equal out to the charge of an ??? (but ???)

a. elementary particles in the sub-sub atomic level. b. ⅓ and ⅔, proton, nucleus 1. up, down 2. two, one; one, two 3. ½ and ⅔, electron, positive

Electric Field - Electric shielding When no ??? (movement of ???) is flowing, the electric field inside metal is ??? - regardless of the field strength outside. Consider a spherical metal ball with electrons on it. *Because of mutual ???, the electrons will spread out ??? over the ??? surface of the ball. *If a test charge was placed at the center of the ball is zero, as the ??? forces ??? in every ???

current, electrons, zero *repulsion, uniformly, outer *opposing, balance, direction.

Electric Energy Storage Because capacitors ??? ??? in an electric field, we can think of it having high ??? energy that can be released. *The amount that can be released is dependent on the capacitor's ??? ??? Discharging a charged capacitor can be a ??? experience, especially the energy transfer occurs where ??? ??? are present - example: *Capacitors can remain ???, even if the electronic device is ??? ??? *More time is required to ??? the energy stored in the Hence the warning signs!

store energy, potential *storage capacity. dangerous, high voltages, like a heavy-duty power supply powering your TV or desktop. *charged, turned off. *discharge, capacitor.