QUIZ 12 1. A switch controls ___ through a circuit. 2. The buildup of electrical charges on an object is called ___. 3. A coil of wire wrapped around an iron core can act as a(n) ___. 4. Materials that let charges flow through them easily are ___. 5. Materials that do not let charges flow through them easily are ___. 6. Electric current that rapidly changes directions is called ___. 7. An object in a circuit that resists the flow of electrons is called a(n) . 8. A device that changes motion into electrical energy is a(n) ___. 9. A(n) ___ is formed when an electric current passes through an unbroken path of conductors. 10. The directions of the magnetic forces around a magnet make up the ___. A. B. C. D. E. F. G. H. I. J. alternating current circuit conductors electric current electromagnet generator insulators magnetic field resistor static electricity QUIZ 13 Circle the letter of the best answer for each question. 1. Which of these is an example of static electricity? A thunder B lightning C clouds D wind 2. The poles of a magnet have the strongest attraction when they are A unlike and close together. B alike and close together. C alike and far apart. D unlike and far apart. 3. Electromagnets are found in A electric motors, speakers, generators, and compasses. B microphones, generators, magnetic fields, and electric motors. C generators, electric motors, microphones, and speakers. D speakers, iron cores, electric motors, and generators. 14. What unit is used to measure resistance? A joules B meters C ohms D volts 15. An electric circuit that produces a magnetic field is called a(n) A current. B magnet. C coil. D electromagnet. QUIZ 14 1. Which of these is a good conductor? A copper B plastic C rubber D wood 2. Study the following chart. 2. A type of circuit that has more than one conductive path is a A parallel circuit. B series circuit. C short circuit. D switch. 3. Which unit is used to measure electrical energy? A watt B amp C volt D ohm 4. A wire that breaks if too much current flows through it is called a(n) A switch. B fuse. C surge protector. D ampere. QUIZ 16 Which event does the chart describe? A electric shock B lightning strike C thunderstorm D tornado 3. Which charge does an object have when positive and negative charges are equal? A static B negative C neutral D positive 4. Why are negative charges more likely to build up when objects are rubbed together? A Negative particles flow more easily. B Positive particles do move. C There are more negative charges. D The two objects both QUIZ 15 Circle the letter of the best answer for each question. 1. Resistance to electricity is measured in A watts. B amps. C volts. D ohms. 1. An electromagnet works because A moving electrons generate magnetic forces. B alternating current completes a circuit. C a generator is powerful. D protons flow through copper wire. 2. An electromagnet is different from a permanent magnet because an electromagnet A is magnetic. B can push and pull. C can attract some metals. D can turn on and off. 3. A device that creates electric current by spinning an electric coil between the poles of a powerful magnet is a(n) A electric motor. B electromagnet. C generator. D maglev train. 4. A device that lowers the voltage of electricity is called A a resistor. B a turbine. C a transformer D a generator. QUIZ 17 Write the word or words that best complete each sentence in the spaces below. Words may be used only once. 1. The flow of electrons through a circuit creates ___. 2. A light bulb is an example of a(n) ___. 3. When objects rub together and electrons are transferred from one object to the other, ___ forms. 4. Electric current that rapidly changes directions is called ___. 5. For electricity to flow, it must follow a complete path called a(n) ___. 6. Wrapping a coil of wire around a metal rod is a simple way to make a(n) ___. 7. Metals such as copper and silver are good ___ . 8. Materials such as wood and plastic are good ___. 9. Two metals that can push or pull each other have ___. 10. A(n) converts mechanical energy into electricity. A. alternating current B. circuit C. conductors D. electric current E. electromagnet F. generator G. insulators H. magnetism I. resistor J. static electricity Circle the letter of the best answer for each question. QUIZ 18 11. A short circuit results when A voltage is too low. B current has little resistance. C a transformer slows down. D a motor turns on. 12. What unit is used to measure electrical energy? A ohms B joules C volts D meters 13. When a permanent magnet is placed near a piece of metal, A the permanent reverses poles. B the piece of metal takes away the magnetic field. C the piece of metal becomes a temporary magnet. D the permanent magnet becomes a temporary magnet. 14. All of the following are examples of devices that use electromagnets except A a doorbell B a refrigerator magnet C a television set D an electric motor 15. Electrical energy that reaches homes and factories is first produced in A an electrical charge. B a production station. C a power plant. D a transformer.