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A molecule of matter can be divided chemically into smaller particles called? - answer atoms Matter consisting of all the same kind of atoms is called an? - answer element Matter consisting of two or more different kinds of atoms is called a? - answer compound The negative charge of a single electron is called a? - answer unit electrical charge Most of the mass of an atom is in the? - answer nucleus When an atom gains an electron, it is called? - answer negative ion Copper is a good conductor, because the copper atom loosely holds it's? - answer valence Gold and silver are good conductor of electricity, because the outer orbits have?
- answer one electron When teo negatively charged rods are brought together, they? - answer repel each other One ampere is equal to? - answer 1 coulomb flowing per second What happens when two unlike materials are rubbed together and then separated? - answer one will be positive and the other negative Connecting two or more metallic objects with a wire or metal strap is called? - answer bonding Grounding minimizes the voltage difference between an object and? - answer ground Humidity has no effect in controlling a static charge on the surface of? - answer only liquids. A static charge is generated by liquids when the liquids are? - answer moving and contact other materials
The charges on the surface of a liquid in a container can be made harmless if the container is? - answer purged Greater static charges are developed on smooth surfaced materials than on rough surfaced materials because of the? - answer larger surface contact What is applied to rubber or that leather belts to prevent the generation of static charges? - answer a conductive dressing The vest way to remove static electricity from machines is to? - answer ground the framework Dust can be removed from the and in a plant by the use of a? - answer electrostatic precipitation The six primary methods of producing a voltage are chemical action , magnetism, friction, - answer heat, light, and pressure Electricity is produced by chemical action in a?p - answer storage battery cell Through which of the following do electrons move in storage battery cell? - answer electrolyte In which type of cell does the chemical action dissolve the negative plate, which cannot be recharged? - answer hot cell Which symbol below represents a battery cell? - answer _-[+ What is copper and iron wire junction called when heated to produce a voltage? - answer thermocouple Photoelectric device convert light energy into? - answer electrical energy What type of cell is a cadmium sulfide (cds) cell? - answer photo conductive Producing voltage by exerting a pressure on a crystalline substance is called? - answer piezoelectric effect What is the purpose of a microphone - answer convert sound waves into electrical signals The two points of maximum attraction on a magnet are called? - answer magnetic materials How do magnetic lines of force always arrange themselves? - answer form closed loops
Which of the following are used to measure electrical resistance? - answer megohmmeter and ohmmeter When property of a material is present in every electrical circuit? - answer resistance Resistors are connected to electrical circuits to? - answer limit current Resistors connected in series across a voltage source to obtain a lower voltage are called voltage? - answer dividers Opposition to any voltage change in a circuit is caused by? - answer capacitance What is the basic unit for measuring the capacitance of a capacitor? - answer farad When capacitors are connected in parallel the effective capacitance of the circuit is - answer increased The opposition to any current change in an a-c circuit caused by inductance is called? - answer inductive reactance What unit is used to measure inductive reactance? - answer ohm Transformers are used to incease or decrease which of the following? - answer voltage The interaction between the rotor and stator in an a-c motor that causes the rotor to rotate is caused by the? - answer magnetic fields Which of the following materials are most commonly used for electrical conductors? - answer aluminum and copper A material which has few free electrons, and therefore is a poor conductor, is called a? - answer insulator What are insulating materials sometimes called? - answer dielectrics As the current in a conductor increases, the heat it generates in the conductor increases? - answer as the square of the current increase What is the definition of a circular mil? - answer the standard unit of measurement for wire cross-sectional areas Dielectric strength is usually expressed in terms of? - answer volts
In simplified terms, what does ohms law state? - answer the higher the resistance in the conductor, the more current in the line for the same voltage Desirable characteristics of conductor insulation include? - answer flexibility and mechanical strength A channel that holds and protects wirs or cables is known as a? - answer race way Bx cable has the same general characteristics as? - answer flexible conduit Electrical current is measured in amperes, which are? - answer coulombs - per- second According to ohms law, voltage is equal to? - answer resistance times current What happens to total current flow if the voltage of a series circuit is doubled and the resistance stays constant? - answer doubles How many paths for current flow will there be in a series circuit that has five resistors? - answer one What is common to sll components of a series circuit? - answer current How many paths for current will there be in a 50-volt circuit having five resistors in parallel? - answer five If one leg of a parallrl circuit develops an open, the total current will? - answer decrease What is common to all components of a parsllel circuit? - answer voltage When the path of a circuit is broken, the circuit is called a? - answer open circuit What device is used to interrupt current flow when a circuit develops a short circuit condition? - answer fuse In a y connected load or source line voltage is found by what formula? - answer el = √3ep The formula for finding line current is a y connected load or source is - answer il = 2 ip In a delta connected load or source the line voltage is found by what formula? - answer el = ep
General purpose transformers are usually - answer dry type A synthetic liquid used in transformers is known as - answer askarel In a dry type transformer the size and operation temperature of the unit is determined by the type of - answer insulation In a diagram below the standard transformer polarity markings are - answer incorrect Distribution transformers are usually made with two secondary or low voltage windings in diagram below two secondary windings are connected in – answer What is Matter? - ANSWER Matter is anything that has mass and occupies space. It contains millions of invisible particles called molecules What is Matter made of? - ANSWER Matter is made of molecules and atoms What is a Molecule? - ANSWER A molecule is the smallest particle into which matter can be divided without changing its identity and still be called by the same name. All molecules are composed of atoms. What is an Electrical Current? - ANSWER It is Electricity in motion and represents the transfer of energy from one place to another and the flow of electrons in a conductor. Electricity is also capable of converting energy from one form to another. Name six sources of power from raw energy - ANSWER Coal, oil, natural gas, uranium, wood & wind. Name the three specialized technical steps that provide electricity - ANSWER Generation, Transmission & Distribution How does a generator plant produced electricity - ANSWER Its produce by turning a shaft, on which is mounted a powerful electromagnet. The shaft turns inside a cylindrical iron shell called a stator. The rotating electromagnetic field, acting on wire coils in the stator, produces electricity. What is a Volt? - ANSWER It is the unit of electrical pressure or electromotive force or potential difference. Electricity flowing along a wire may be compared to water flowing through a pipe.
What is the atom? - ANSWER It is the smallest particle that makes up that type of material called an ELEMENT. What retains its characteristics when subdivided into atoms? - ANSWER Elements What is the core of the atom called - ANSWER Nucleus Where is most of the mass of the atom concentrated in? - ANSWER Nucleus What does the Nucleus contain? - ANSWER It contains PROTONS (positively charged particles) and NEUTRONS (electrically neutral). What are the six primary methods of producing a voltage (EMF) to cause an electric current to flow? - ANSWER Chemical action, magnetism, friction, Heat, light & Pressure. When two points that have an electrical potential difference are joined by a conductor, ______ results. - ANSWER Current flow The term voltage and potential are both used to indicate the electrical ______ in a system. - ANSWER Pressure In an electrical system, the potential is provided by a storage _____, a mechanically driven ______, or a dry cell. - ANSWER Battery; generator An electrical current is produced when an applied voltage sets the free ____ of material in motion. - ANSWER Electrons Materials that have few free electrons are called ______? - ANSWER INSULATORS. Mica, porcelain, glass, bakelite and silicone are good insulating material. If a battery is connected to the two ends of a wire, the electron movement in the wire is toward the _______ battery terminal. - ANSWER Positive The electron movement along the conductor of a circuit is the same everywhere, provided the applied _________ remains constant. - ANSWER Voltage Molecule Smallest parts of substance can be physically divide into two compose more Atoms. A molecule is a collection of atoms held together by strong forces called chemical bonds. Atom
That electrodes of a cell shaped as plates to expose a surface as possible to the electrolytes. Storage battery Several secondary cell connected together for either a great voltage or current output Magnetism A certain force exhibit by some materials which gives them the ability to attract other materials. Principally Iron or its alloys Natural magnet (Lode stone) certain type of mineral are which has the natural properties of a magnet Line of Force Invisible lines along which magnetic energy travels from one pole of a magnet to the other Artificial magnet Iron and certain alloys of iron which are magnetized by artificial means Permanent magnet Hardened steel which has been magnetize artificially and which retains its magnetic properties Magnetic field The area surrounding it magnet in which magnetic properties are exhibit Magnetic pole The opposite ends of magnet where the magnetism is concentrated. Each magnet has two pole, designated as north and south Magnetic circuit The complete path through which the lines of force travel, leaving the North Pole and re-entering the South Pole Magnetic material A material which can be magnetized, principally iron Non-Magnetic material A material which cannot be magnetized example wood, glass, brass, rubber Electric generator A machine which utilizes magnetism to produce an EMF and consequently, electric circuit. Electro-motive force (EMF) the force created by an electric generator (or by other means) which causes current to flow.(same as voltage, volts, Electric potential, pressure) Volt The unit of Electro-motive force Factor governing the Value of EMF of a Generator A. Speed of conductors cutting lines of force. B. Strength of the magnetic feel. C. Length of conductors cutting through the field. Resistance Opposition of the current flow Impedance
Total and complete opposition to the flow of electrons Factors Governing Resistance A. Materials it self(Atomic structure- Good conductor or bad) B. Length of the conductor C. Cross-sectional area(sizable) D. Temperature Ohm's Law Shows relationship between current, voltage,wattage, and resistance Ohm's law formula Electrical circuit A complete Path provided for the flow of electrons. Consists of a source, with a closed conducting path leading from the source and back to the source. Resistor Any device which may be placed in the circuit and which offers opposition to the flow of electrons around the circuit Series circuit A circuit with only one path for current to flow. There are no branches Parallel circuit A circuit with more than one path. Current branches to flow in every available Path Voltage drop The voltage dissipation between and two points in a circuit. The voltage "dropped " or "dissipated in a forcing currents through a resistance Short circuit A very low resistance path placed in circuit in such a manner as to allow an excessive current flow Series, Parallel Circuit A circuit in which there is resistance (load) connected both in series and parallel Cross phase A short circuit between two energize conductors and a ground phase. Very high current flow. Matter Matter is permanent it cannot be destroy or created and it takes up space. All matter is composed of extremely small particles call atoms. Elements When like Atoms are bound together chemically, They form molecules of an element. A molecule is the smallest division which can be made to a substance and still retain all the properties
