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ELECTRICAL CRAFT HELPER EXAM
QUESTIONS WITH ANSWERS
Shells Any of the space occupied by the orbit of a group of electrons of approximately equal surrounding the nucleus of an atom Static electric charge Electric charge at rest Caused by friction of materials, where a a surplus of electrons exists and may be discharged. Electron flow The condition where the free electrons are cause to move in the same direction along or through a conductor Current Occurs when a stream of electrons are caused to move through a conductor Ampere
Rate of electron flow (current flow). When one "coulomb" of electrons pass a given point in one second. Primary cell A cell which is composed of certain materials which are use during the process of delivering electric current Electrode The dissimilar metals which are place in an electrolyte to form a cell. Electrolyte The liquid solution (sometimes a paste) in which the electrodes are place. Secondary cell A cell which is rechargeable. Use materials which change in composition during delivery of current, but may restore to original condition upon recharge Plates 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
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. 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 Fundamental constituents of matter. The elements wich come together in various combination to form molecules of many substances Nucleus The center portion of an atom which has a positive electrical charge Proton Single positive electrical charge located in the middle of an atom. Electron Single negative electric charge orbits around the nucleus some and Paths close to the nucleus others and Paths varying distance from the nucleus Coulomb Certain quantity of electrons. The unit of measure that specified the rate at which electric current flows per second Bound Electrons Those electrons in orbit nearest the nucleus, not Easily dislodged from their normal orbit.
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
