Electric Fields and Potential Nathaniel Yoder, Brooke Young, Brandon Mock

Major Concepts Electric charges have electric fields that are similar to magnetic fields. Electric field lines are a vector quantity and represent the action between a field and a positive electrical force. The inside of a charged conductor has an electric field that is usually zero. this is why if you don't get shocked by lightning if you are inside your car.

Historical Perspective the idea of eleteric fields were first introduced by michael faraday. which he created a faraday sheild, in 1836, to block eletric fields. it cannot block stable or slowly varying fields. Nikola tesla in mid 1890's tried to build a wireless power structure. using a magnetic amplifier to conduct over larger distance.

Conceptual Applications Electrical field lines are used to describe an electric field based on the direction of the force on a posotive charge, and the strength of the force. Electric sheilding is used in conductors. Electrical potential is used in determining the electric potential of a charge. An apparatus used to raise high voltages is a van de graaff generator.

Think and Explain 1) how is an eletric field different than a gravitational field? gravitational field is created by mass while eletric field is created by a charge 2) the vectors gor gravitational field of the earth point toward the earth; the vectors for the eletric fieldof a proton point away from the proton. explain. The field vector points in the direction a tiny imaginary test particle would move. The test particle for gravity is a tiny mass. Masses move toward the Earth. The test particle for electric fields is a tiny positive particle. Positives repel, so the electric field vector points away from a proton and toward an electron. 3) if a free electron and free proton were placed in an eletric field, how would their accelerations and directions of travel compare? the electro n will have greater speed as its less massive, the electron will go oposite direction as proton. 4) suppose that the strengthof the eletric field about an isolated point charge has a certain value at a distance of 1 metre. how will the eletric field strenght compare at a distance of 2 metre from the point charge? what law guides your answer? as it increases by a factor of two, divide the strength by four. inverse square law 5) when a conducter is charged, the charge moves to the outer surface of the conducter. why is this so? the eletric field inside the conducter equals zero.

Cont. 6) suppose that a metal file cabinent is charged.how will the chrage concentration at the corners of the cabinent compare to the charge concentration on the flat parts of the cabinent? Defend yer answer the corners will have more charge concentrated there because the electric field will be higher at the points. 7)if you have 12J of work to push .001C of charge into an electric field, how much will the voltage increase? when the charge is realesed what will its kinetic energy be as it flies past its starting point? what principle guides yer answer? 12000 v, The principle of conservation of energy says that the energy released will be equal to the energy put into the system, so the kinetic energy of the charge as it flies back past its starting point will be 12 J. 8)if you have 24J of work to push .002 C of charge into an electric field, how much will the voltage increase? when the charge is realesed what will its kinetic energy be as it flies past its starting point? what principle guides yer answer? 12000, The principle of conservation of energy says that the energy released will be equal to the energy put into the system, so the kinetic energy of the charge as it flies back past its starting point will be 12 J. 9)is it correct to say an objject with twice the electrice potential as another has twice the eletric pontential energy? Defend yer answer. no because the electric potential is equal to the volts it has. 10)why does your hair stand out when you are charged by a device such as van de graff generator? charges in your hair repel from those conducted from the generator

Review 1. The objects don't touch. 2. The field is touching the object. 3. They both have force. 4. It is called this because it has magnitude and direction. 5. a. They show where the force is. b. the directions are based on the field's reaction to a posotive force. 6. The closer the lines the stronger the charge. The more spread out the weaker the charge. 7. The lines are equally long. 8. This is because the car is a charged conductor, and the inside of charged conductors is normally an electric field force of zero. 9. The electric field inside a charged conductor is zero anywhere inside the conductor. 10. a. no, gravity only attracts b. Yes, the object being sheilded has to be surrounded by a charged surface.

Cont. 11. The more work on a charged partice, the more its potential energy increases. 12. If work is done to overcome electrical repulsion the potential energy is increased. 13. The charged particle's potential energy will convert into kinetic energy as it accelerates away. 14. Electric potential is the electric potential energy divided by the charge. 15. The electric potential is not increased because electric potential is the electric potential energy divided by the charge. increasing both will result with the same answer. 16. Volts 17. Yes because the volts woulds equal zero if there was no charge. 18. Electric potential can be high if the electric potential energy is low by having an extremely low charge. 19. the amount of charge in the inside surface is low, and high on the outside. 20. A sphere with a radius of 1m can have 3 million volts before electrical discharge.

Background Information The space around a concentration of electric charge is different from how it would be if the charge were not there. When standing by a charged dome you could feel the charge. The hair on your body would stand up slightly when you are more than a meter away and stand up more the closer you are to it. Same thing with the space around a black hole, and a magnet. This space is known as the force field.

Question and Conduct When placing a paper clip between two magnets how will the paper clip move? To conduct this experiment we will use two magnets and a paperclip. we will place the two magnets a little bit apart from each other and place a paperclip in between to see how the paper clip will react.

Material & Procedure 1. Two Magnets 2. A paperclip 1. Place the two magnets slightly apart from each other and hold them 2. Have another person place the paper clip in the middle of the two magnets 3. Record the results. Don't get pinched by the magnes, or stabbed by the paper clip

Mag. Mag. O ^ O Papclp (paperclip keeps spinning)

Analysis After performing the experiment we found when holding the magnets, if the north side of the magnet was facing the paper clip, the south side of the paper clip would turn towards the magnet. When there was two magnets present with both north sides facing in, the paper clip spun in circles.

Conclusion The paper clip spun in circles because two north or two south sides were facing each other preventing the magnet from connecting to one magnet. Both were repelling at opposite times. After performing the experiment, we found the paperclip tried to line up perfectly with the magnets. It tried to follow "opposites attract" but when two north sides were facing in the paperclip kept spinning trying to find a place to go.