Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Mains electricity wikipedia , lookup
Mechanical-electrical analogies wikipedia , lookup
Ground (electricity) wikipedia , lookup
Electronic engineering wikipedia , lookup
Stray voltage wikipedia , lookup
History of electromagnetic theory wikipedia , lookup
Electrical engineering wikipedia , lookup
Name: ____________________________________________ Group: __________ Support activities – Second Year of Secondary Cycle Two ACTIVITY 19 ANSWER KEY Date: __________________ ST STUDENT BOOK: Chapter 5, pages 140–143 RELATED HANDOUT: Concept review 19 Electricity and electrical charges 1. Complete the following sentences, using the words or groups of words in the box below. You may not need some words, and you may use others more than once. • • • • • • • • • • • area of space atom attract each other charges charging conductivity conductors contact coulomb direction electrical • • • • • • • • • • • electrical charge electrical effect electrical field electrical field lines electrical force electrically charged electrodes electrolytic solutions electron(s) electronic fewer electrons • force • freely • imbalance • insulators • law of conservation of charge • like signs • lines • metalloids • metals • more electrons • • • • • • • • • • • negative negative ions negative terminal neutral nonmetals positive positive charges protons valence electrons without yellow amber a) Electrical phenomena were discovered a long time ago (circa 600 BCE) when people electrical effect yellow amber noticed the _______________________ produced by rubbing ________________________ against wool: the amber could then attract small objects. From this observation and others © ERPI Reproduction and adaptation permitted solely for classroom use with Observatory. that followed, scientists concluded that any material that attracts small objects after being electrically charged rubbed is ________________________ . b) In the 18th century, Benjamin Franklin determined the existence of positive and negative charges ________________________, which could be transferred from one object to another. atom In the 19th century, after the discovery of the ________________________ , the source of charges the ________________________ that cause electrical phenomena became clearer. protons c) The atom is composed of ________________________ in its nucleus and of electrons ________________________ that gravitate around the nucleus in electron shells. Valence electrons ________________________ can be transferred from one atom to another. The protons positive carry a ________________________ charge, and the electrons carry a negative neutral ________________________ charge. Since atoms are ________________________ , they contain as many protons as electrons. Observatory / Guide 11129-B 1 ANSWER KEY Support activities – Second Year of Secondary Cycle Two ACTIVITY 19 Electricity and electrical charges Name: ____________________________________________ Group: __________ Date: __________________ Electrical charge d) ________________________ is a property of protons and electrons: the proton carries a positive charge, and the electron carries a negative charge. A negatively charged body more electrons contains ________________________ than protons. A positively charged body contains fewer electrons ________________________ than protons. coulomb e) The unit of measurement for electrical charge is the ________________________ (C). electrical charge In equations, ________________________ is represented by the variable “q.” electron f) The elementary charge, which is the charge carried by an ________________________ or -19 coulomb a proton, has a value of 1.602 10 C. A ________________________ is equal to the charge of 6.25 1018 electrons or protons. g) Studies of electrically charged matter have revealed the following facts: like signs – Electrical charges of ________________________ repel each other. attract each other – Electrical charges of opposite signs ________________________ . electrical force – The ________________________ is the force at work in the attraction or repulsion between charges. law of conservation of charge , electrical charges can be neither created – According to the ________________________ nor destroyed. They can only be transferred from one body to another. neutral h) Most objects are electrically ________________________ because they carry an equal number of positive and negative charges. However, they can exchange electrons. We can © ERPI Reproduction and adaptation permitted solely for classroom use with Observatory. imbalance create an ________________________ in the charge of an object by charging ________________________ matter. conductors i) Matter can be divided into three categories: ________________________ , semiconductors and insulators. metals j) In general, ________________________ and electrolytic solutions are good conductors. freely Electrical charges can flow through them ________________________. When metal conductors are placed in an electrical circuit, the electrons move in one direction ________________________ , causing the charge to move along the length of the circuit. electrons The ________________________ go from one atom to another, creating an electric electrolytic solutions current. In the case of ________________________ , the substances contain positive electrodes and negative ions. When ________________________ are placed in this type of solution, negative terminal the positive ions move toward the ________________________ , and the negative ions ________________________ move toward the positive terminal. The current can then flow through the solution. Observatory / Guide 11129-B 2 ANSWER KEY Support activities – Second Year of Secondary Cycle Two ACTIVITY 19 Electricity and electrical charges Name: ____________________________________________ Group: __________ Date: __________________ conductivity k) Semiconductors are substances of variable ________________________ depending on electronic several factors. They are used in ________________________ circuits to slow the flow of Metalloids electric current. ________________________ and carbon are semiconductors. Insulators l) ________________________ are substances that impede the flow of electric current. The freely charges, which cannot flow ________________________ , stay in the same place. These nonmetals substances include ________________________ as well as wood, plastic and ceramic. 2. True or false? a) The positive charge of an object comes from the transfer of protons. False b) The unit of measurement for electrical charge is the watt. False c) The human body conducts electricity. True 3. Are the following substances conductors, semiconductors or insulators? a) the porcelain that holds wires on utility poles An insulator A conductor c) a resistor in a printed circuit A semiconductor d) the filament in a light bulb A conductor e) the rubber coating around a wire An insulator © ERPI Reproduction and adaptation permitted solely for classroom use with Observatory. b) a copper wire in an electronic circuit Observatory / Guide 11129-B 3 ANSWER KEY Support activities – Second Year of Secondary Cycle Two ACTIVITY 19 Electricity and electrical charges