Section 20.1 Electric Charge and Static Electricity (pages )

Transcription

1 Nme Clss Dte Section 20.1 Electric Chrge nd Sttic (pges ) This section explins how electric chrge is creted nd how positive nd negtive chrges ffect ech other. It lso discusses the different wys tht electric chrge cn e trnsferred. Reding Strtegy (pge 600) Identifying Min Ides Copy the tle on seprte sheet of pper. As you red, write the min ides. For more informtion on this Reding Strtegy, see the Reding nd Study Skills in the Skills nd Reference Hndook t the end of your textook. Topic Electric Chrge Electric Forces Chrcteristics of Electric Chrge Min Ide An excess or shortge of electrons produces net electric chrge. Like chrges repel nd opposite chrges ttrct. Electric Fields Sttic The strength of field depends on the net chrge nd distnce from the chrge. Chrge cn e trnsferred y friction, contct, nd induction. Person Eduction, Inc., pulishing s Person Prentice Hll. All rights reserved. Electric Chrge (pges ) 1. Wht re the two types of electric chrge?. Positive. 2. Is the following sentence or? In n tom, negtively chrged electrons surround positively chrged nucleus. 3. Is the following sentence or? If neutrl tom gins one or more electrons, it ecomes positively chrged ion. 4. Wht is the SI unit of electric chrge? Negtive The coulom Electric Forces (pge 601) 5. Circle the letter of ech sentence tht is out electric force.. Like chrges ttrct nd opposite chrges repel.. Electric force is the ttrction or repulsion etween electriclly chrged ojects. c. Electric force is inversely proportionl to the mount of chrge. d. Electric force is inversely proportionl to the squre of the distnce etween two chrges. Physicl Science Reding nd Study Workook 239

2 Person Eduction, Inc., pulishing s Person Prentice Hll. All rights reserved. Nme Clss Dte 6. Which re stronger inside n tom, electric forces or grvittionl forces? Electric forces re stronger. 7. Is the following sentence or? Electric forces cuse friction nd other contct forces. Electric Fields (pge 602) 8. A chrge s electric field is the effect the chrge hs on other chrges in the spce round it. 9. Circle the letters of the fctors tht the strength of n electric field depends on.. the direction of the field. whether the chrge is positive or negtive c. the mount of chrge tht produces the field d. the distnce from the chrge 10. Is the following sentence or? The field of negtive chrge points wy from the chrge. Sttic nd Chrging (pges ) 11. Sttic electricity is the study of the ehvior of electric chrges. 12. Is the following sentence or? Chrge cn e trnsferred y friction, y contct, nd y induction. 13. Wht is the lw of conservtion of chrge? is constnt. The totl chrge in n isolted system 14. Ruing lloon on your hir is n exmple of chrging y friction. 15. A chrge trnsfer etween ojects tht touch ech other is clled chrging y contct. 16. Circle the letter of ech sentence tht is out chrging.. When you ru lloon on your hir, your hir loses electrons nd ecomes positively chrged.. The sphere of Vn de Grff genertor trnsfers ll of its chrge to you when you touch it. c. Induction occurs when chrge is trnsferred without contct etween mterils. d. Sttic chrges cnnot move. Sttic Dischrge (pge 603) 17. Is the following sentence or? Sttic dischrge occurs when pthwy through which chrges cn move forms suddenly. 18. How does lightning occur? Negtive chrge in the lower prt of storm cloud induces positive chrge in the ground elow the cloud. Eventully the ir ecomes chrged, forming pthwy for the electrons to trvel from the cloud to the ground. 240 Physicl Science Reding nd Study Workook

3 Nme Clss Dte Section 20.2 Electric Current nd Ohm s Lw (pges ) This section discusses electric current, resistnce, nd voltge. It lso uses Ohm s Lw to explin how voltge, current, nd resistnce re relted. Reding Strtegy (pge 604) Predicting Before you red, write prediction of wht electric current is in the tle elow. After you red, if your prediction ws incorrect or incomplete, write wht electric current ctully is. For more informtion on this Reding Strtegy, see the Reding nd Study Skills in the Skills nd Reference Hndook t the end of your textook. Electric Current Proly Mens Smple nswer: Current is moving chrge. Electric Current Electric Current Actully Mens Electric current is continuous flow of chrge. Electric Current (pge 604) 1. Wht is electric current? Electric current is continuous flow of chrge. Person Eduction, Inc., pulishing s Person Prentice Hll. All rights reserved. 2. Complete the following tle out electric current. Electric Current Type of Current How Chrge Flows Exmples Direct One direction Flshlight Alternting Two directions Home or school 3. Electrons flow in the wire from (n) terminl to (n) positive terminl. Conductors nd Insultors (pge 605) 4. Wht is n electricl conductor? chrge cn esily flow. 5. Wht is n electricl insultor? cnnot esily flow. negtive An electricl conductor is mteril through which An electricl insultor is mteril through which chrge 6. Is the following sentence or? Metls re good conductors ecuse they do not hve freely moving electrons. Physicl Science Reding nd Study Workook 241

4 Person Eduction, Inc., pulishing s Person Prentice Hll. All rights reserved. Nme Clss Dte Mtch ech mteril to the ctegory of conductor or insultor. Mteril Ctegory 7. Copper. conductor 8. Plstic. insultor 9. Ruer 10. Silver 11. Wood Resistnce (pge 605) 12. Explin why the current is reduced s electrons move through conductor. The electrons collide with electrons nd ions. These collisions convert some kinetic energy into therml energy, leving less energy to move the electrons. 13. Circle the letter of ech fctor tht ffects mteril s resistnce.. its length. its temperture c. its velocity d. its thickness 14. Wht is superconductor? when it is cooled to low tempertures. A superconductor is mteril tht hs lmost zero resistnce Voltge (pge 606) Mtch ech term to its definition. Definition Term c 15. A device tht converts chemicl energy to electricl energy 16. Requires complete loop 17. The difference in electricl potentil energy etween two plces in n electric field. flow of chrge. voltge c. ttery 18. Is the following sentence or? Three common voltge sources re tteries, solr cells, nd genertors. Ohm s Lw (pge 607) 19. Is the following sentence or? According to Ohm s lw, the voltge in circuit equls the product of the energy nd the resistnce. 20. Douling the voltge in circuit doules the current if resistnce is held constnt. 21. Is the following sentence or? Douling the resistnce in circuit will hlve the current if voltge is held constnt. 242 Physicl Science Reding nd Study Workook

5 Nme Clss Dte Section 20.3 Electric Circuits (pges ) This section descries circuit digrms nd types of circuits. It lso explins clcultion of electric power nd electric energy nd discusses electricl sfety. Reding Strtegy (pge 609) Relting Text nd Visuls As you red out household circuits, complete the tle y listing three things the digrm in Figure 13 helps you understnd out circuits. For more informtion on this Reding Strtegy, see the Reding nd Study Skills in the Skills nd Reference Hndook t the end of your textook. Understnding Circuit Digrm Wht Cn Be Seen in the Circuit Digrm? Wire ringing current from outside Grounding wire Seprte circuit for the lights Seprte circuit for the dryer Person Eduction, Inc., pulishing s Person Prentice Hll. All rights reserved. Circuit Digrms (pges ) 1. Circuit digrms use to represent prts of circuit, including source of electricl energy nd devices tht re run y the electricl energy. Mtch ech symol to wht it indictes on circuit digrm. Symol Wht Symol Indictes c Series Circuits (pge 610) 5. Is the following sentence or? In series circuit, if one element stops functioning, then none of the elements cn operte. 6. Explin why the uls shine less rightly when more uls re dded to series circuit. the current. Prllel Circuits (pge 610) symols. The direction of current. A negtive terminl c. A positive terminl Adding more uls increses the resistnce, which decreses 7. Is the following sentence or? Circuits in home re rrely wired in prllel. 8. If one element stops functioning in prllel circuit, the rest of the elements cn still operte. Physicl Science Reding nd Study Workook 243

6 Person Eduction, Inc., pulishing s Person Prentice Hll. All rights reserved. Nme Clss Dte Power nd Energy Clcultions (pges ) 9. The rte t which electricl energy is converted to nother form of energy is clled electric power. 10. The SI unit of electric power is the joule per second, or wtt, which is revited W. 11. Is the following sentence or? Electric power is clculted y multiplying current times voltge. 12. Write the formul for clculting electricl energy. E P t 13. The unit of energy usully used y electric power compnies is the kilowtt-hour. Electricl Sfety (pges ) 14. Circle the letters of wht could hppen if the current in wire exceeds the circuit s sfety limit.. The wire could overhet.. The wire could get cooler. c. A fire could strt. d. A fuse could low. 15. Explin how fuse prevents current overlod in circuit. fuse melts, which stops the flow of chrge in the circuit. A wire in the center of the 16. A switch tht opens to prevent overlods when current in circuit is too high is clled (n) circuit reker. 17. Explin why touching n electricl device with wet hnds is dngerous. Your hnds conduct electricity more redily when they re wet. 18. Is the following sentence or? A ground-fult circuit interrupter shuts down the circuit if the current flowing through the circuit nd current returning to ground re equl. 19. The trnsfer of excess chrge through conductor to Erth is clled grounding. 20. Complete the following tle out equipment used to prevent electricl ccidents. Equipment to Equipment to Equipment to Prevent Current Protect People Prevent Short Overlod from Shock Circuits. Fuse. Insultion e. Insultion Circuit reker c. Three-prong plug Grounding wire d. Ground-fult circuit interrupter 244 Physicl Science Reding nd Study Workook

7 Nme Clss Dte Section 20.4 Electronic Devices (pges ) This section discusses how vrious electronic devices operte nd wht they re used for. Reding Strtegy (pge 618) Summrizing Copy the tle on seprte sheet of pper. As you red, complete the tle to summrize wht you lerned out solidstte components. For more informtion on this Reding Strtegy, see the Reding nd Study Skills in the Skills nd Reference Hndook t the end of your textook. Solid Stte Components Solid-Stte Component Description Uses Diode Electrons flow from n Chnge lternting current n-type to p-type to direct current semiconductor. Person Eduction, Inc., pulishing s Person Prentice Hll. All rights reserved. Trnsistor Integrted Circuit Electronic Signls (pges ) Mtch ech term to its definition. c d Definition A smll current flows through the middle lyer of three lyers of semiconductors, chnging the resistnce. A thin slice of silicon tht contins mny solid-stte components 1. Informtion sent s ptterns in the controlled flow of electrons through circuit 2. The science of using electric current to process or trnsmit informtion 3. A smoothly vrying signl produced y continuously chnging the voltge or current in circuit 4. A signl tht encodes informtion s string of 1 s nd 0 s Switch, mplifier Moile phones, pgers, computers Term. electronics. nlog signl c. electronic signl d. digitl signl 5. Which type of signl is usully used y n AM rdio sttion? Anlog signls re used y AM rdio sttions. 6. Is the following sentence or? Anlog signls re more relile thn digitl signls. Physicl Science Reding nd Study Workook 245

8 Person Eduction, Inc., pulishing s Person Prentice Hll. All rights reserved. Nme Clss Dte Vcuum Tues (pge 619) 7. Circle the letter of ech item tht is out vcuum tues.. cn chnge lternting current to direct current. never urn out c. cn increse the strength of signl d. cn turn current on or off 8. Is the following sentence or? An imge is produced in CRT when phosphors glow red, green, nd lue in response to electron ems. Semiconductors (pge 621) 9. Wht is semiconductor? only under certin conditions. A semiconductor is crystlline solid tht conducts current 10. Nme the two types of semiconductors.. p-type. n-type 11. Circle the letter of ech sentence tht is out p-type semiconductor.. It cn e mde y dding trce mount of oron to silicon.. Electrons re ttrcted to positively chrged holes t ech oron tom. c. As the electrons jump from hole to hole, it looks like flow of positive chrge. d. Boron toms provide wekly ound electrons tht cn flow. 12. Is the following sentence or? In n n-type semiconductor, wekly ound electrons cn conduct current. Solid-Stte Components (pges ) Mtch ech term to its definition. Term c 13. diode 14. trnsistor 15. integrted circuit Definition. A solid-stte component with three lyers of semiconductors. A thin slice of silicon tht contins mny solid-stte components c. A solid-stte component tht comines n n-type nd p-type semiconductor 16. A chip or microchip is nother nme for (n). Communictions Technology (pge 622) 17. Why is it useful for communiction devices to use microchips? them more portle, relile, nd ffordle. integrted circuit Microchips mke 18. A moile phone cn store dt such s phone numers ecuse cpcitors store electric chrge 246 Physicl Science Reding nd Study Workook.