ELECTRICAL TRAINING FINAL EXAM This is the final exam for the electrical training course. You will have 1 hour to complete the exam. This exam must be completed in 60 minutes. Click here to start the exam Time left: 3600 1. Conventional Current Flow is current flow from positive to negative potentials a. True b. False2. Conventional Current Flow is current flow from positive to negative potentials a. True b. False3. A shunt-wound DC motor has a decreasing torque as speed increases. a. True b. False4. A series-wound motor has a rapidly increasing torque when speed decreases. a. True b. False5. Electron current, or amperage, is described as the movement of free electrons through a conductor. a. True b. False6. Resistance is defined as all opposition to current flow. a. True b. False7. In 1827, George Simon Ohm discovered that there was a definite relationship between voltage, current, and resistance in an electrical circuit. a. True b. False8. The speed of a DC motor may be changed by using resistors to vary the field current and, therefore, the field strength. a. True b. False9. As load is removed from a shunt-wound motor, the speed will increase sharply. a. True b. False 10. The advantages of a series-wound motor are that it develops a large torque and can be operated at low speed. a. True b. False11. Starting resistors are necessary for large DC motors to prevent damage due to high currents while starting the motor. a. True b. False12. Magnetism is a result of ___________ spinning on their own axis around the nucleus. A. Protons B. Neutrons C. Electrons D. None of the above 13. In magnetic materials, the atoms have certain areas called domains. a. True b. False14. Domains are aligned such that their electrons tend to spin in opposite directions. a. True b. False15. The law of magnetism states that like magnetic poles repel and unlike magnetic poles attract. a. True b. False16. The group of magnetic field lines emitted outward from the north pole of a magnet is called magnetic flux. a. True b. False 17. Air, which is nonmagnetic, has a very high BH profile. a. True b. False 18. The permeability (μ) of a magnetic material is the ratio of B to H. a. True b. False 19. The magnetic flux in an iron core lags behind the magnetizing force. a. True b. False 20. The hysteresis loop is a series of curves that show the characteristics of a magnetic material. a. True b. False 21. The maximum number of electrons that can fit in the outermost shell of any atom is 18. a. True b. False 22. The electrons in the outermost shell are called valence electrons. a. True b. False 23. A battery consists of two or more chemical cells connected in series. a. True b. False 24. The chemical cell is composed of two electrodes made of different types of metal or metallic compounds which are immersed in an electrolyte solution. a. True b. False 25. A line diagram is used to show the relationship between component groups, or stages in a circuit. a. True b. False 26. The total voltage across a DC series circuit is equal to the sum of the voltages across each resistor in the circuit. a. True b. False 27. The voltage flowing through each branch of a DC parallel circuit is equal to the total voltage in the circuit. a. True b. False 28. The proton carries a single unit positive charge equal in magnitude to the electron charge. a. True b. False 29. The electrons attraction to the nucleus is called __________ . A. electrostatic field B. electrostatic attraction C. electrostatic force D. potential difference 30. The Electrostatic Field is a force acting between charged objects that causes Them to repel or attract. a. True b. False 31. To produce current, the electrons must be moved by a potential difference. a. True b. False 32. Atoms with only one valence electron make good ____________ . A. Insulators B. Semiconductors C. Conductors D. Resistors 33. All voltages and currents have polarity as well as magnitude. a. True b. False 34. The direction of electron flow is from a point of negative potential to a point of positive potential. a. True b. False 35. The direction of positive charges, or holes, is in the opposite direction of electron flow. This flow of positive charges is known as “conventional flow.” a. True b. False 36. Kirchhoff’s voltage law states that the sum of the voltage drops around a closed loop is equal to the sum of the voltage sources of that loop. a. True b. False 37. Kirchhoff’s current law states that the current arriving at any junction point in a circuit is equal to the current leaving that junction. a. True b. False 38. The voltage flow at any element in a DC circuit can be determined using loop equations. a. True b. False 39. The voltage at any point in a DC circuit can be determined using node equations. a. True b. False 40. An open series DC circuit will result in no power being consumed by any of the loads. a. True b. False 41. An will oppose a change in current flow by the CEMF induced when the field collapses or expands. a. Resistor b. Inductor c. Capacitor d. None of the above 42. A capacitor is constructed of two conductors (plates) separated by a dielectric. a. True b. False 43. An electrolyte is a solution which is capable of conducting an electric current. The electrolyte of a cell may be a liquid or a paste. a. True b. False 44. Specific gravity is defined as the ratio comparing the weight of any liquid to the weight of an equal volume of water. a. True b. False 45. A good example of a voltaic cell is one that contains iron and copper electrodes. a. True b. False 46. The purpose of a battery is to store chemical energy and to convert this chemical energy into electrical energy when the need arises. a. True b. False 47. A battery that is connected in parallel has the advantage of a greater . a. Voltage b. Shelf life c. Current carrying capacity d. None of the above 48. As load is removed from a shunt-wound motor, the speed will increase sharply. a. True b. False 49. To reduce the amount of gassing, charging voltages above volts per cell should be minimized. a. 6 b. 5.5 c. 2.30 d. 12 50. Counter-electromotive force (CEMF) is defined as the induced voltage that acts to counter the applied voltage in a DC motor or a DC generator. a. True b. False 51. Applied voltage is defined as the current that is delivered across the load. a. True b. False 52. The of an over-compounded DC generator gradually rises with an increasing load. a. Voltage b. Counter electro motive force (cemf) c. Current d. a and b 53. In a differentially-compounded DC generator, the series and shunt fields oppose one another. a. True b. False 54. The speed of a DC motor may be changed by using resistors to vary the field current and, therefore, the field strength. a. True b. False 55. A series-wound motor has a rapidly increasing torque when speed decreases. a. True b. False 56. The advantages of a series-wound motor are that it develops a large torque and can be operated at low speed. a. True b. False 57. Starting resistors are necessary for large DC motors to prevent damage due to high currents while starting the motor. a. True b. False 58. A simple generator consists of a conductor loop turning in a magnetic field, cutting across the magnetic lines of force. a. True b. False 59. The sine wave output is the result of one side of the generator loop cutting lines of force. a. True b. False 60. Effective value of AC equals effective value of DC. a. True b. False 61. A shunt-wound DC motor has a decreasing torque as speed increases. a. True b. False 62. Phase angle is used to compare two wave forms. a. True b. False 63. As the generator coil rotates 180°, the output voltage goes through one complete cycle. a. True b. False 64. The alkaline cell has the advantage of an extended life over that of a carbon-zinc cell of the same size. a. True b. False 65. The nickel-cadmium battery has the advantage of being a dry cell that is a true storage battery with a reversible chemical reaction. a. True b. False 66. Which device below operates on the principals of inductance? a. Resistor b. Motor c. Light bulb d. All of the above 67. Opposition to the flow of alternating current caused by inductance is called capacitive reactance. a. True b. False 68. Current leads voltage by 90 degrees in a purely capacitive circuit. a. True b. False 69. Impedance is the total opposition to current flow in an AC circuit. a. True b. False 70. Impedance is equal to total resistance. a. True b. False 71. R-C-L series circuit at resonance is when net reactance is zero and circuit current output is determined by the series resistance of the circuit. a. True b. False 72. R-C-L parallel circuit at resonance is when net reactance is maximum and circuit current output is at minimum. a. True b. False 73. In AC circuits, current and voltage are normally in phase and, as a result, not all the power produced by the generator can be used to accomplish work. a. True b. False 74. While direct current has one form of power, alternating current has three different forms of power that are related in a unique relationship. a. True b. False 75. True power is the power delivered to an electrical circuit. a. True b. False 76. Apparent power is the power consumed by the resistive loads in an electrical circuit. a. True b. False 77. Reactive power is the power consumed in an AC circuit because of the expansion and collapse of magnetic and electrostatic fields. a. True b. False 78. Reactive power is not useful power because it is stored in the circuit itself. a. True b. False 79. The total power delivered by the source is the apparent power. a. True b. False 80. Power factor is the ratio between true power and apparent power. a. True b. False 81. In a three phase system each phase is out of phase with each other. a. 90 degrees b. 120 degrees c. 180 degrees d. 0 degrees 82. Unbalanced three-phase circuits are indicated by abnormally high currents in one or more of the phases. a. True b. False 83. Slip rings are electrical connections that are used to transfer power to and from the rotor of an AC generator. a. True b. False 84. Efficiency of an AC generator can be calculated by dividing the output by the input and multiplying by 100. a. True b. False 85. The frequency of the generated voltage in an AC generator can be calculated by multiplying the number of by the speed of the generator and dividing by a factor of 120. a. Windings b. Coils c. Poles d. Phases 86. The advantage of the delta-connected AC generator is that if one phase becomes damaged or open, the remaining two phases can still deliver three-phase power at a reduced capacity of 57.7%. a. True b. False 87. The advantage of a wye-connected AC generator is that each phase only has to carry 57.7% of line voltage and, therefore, can be used for high voltage generation. a. True b. False88. The purpose of a voltage regulator is to maintain the output current of a generator at a desired value. a. True b. False 89. It is virtually impossible for the rotor of an AC induction motor to turn at the same speed as the rotating magnetic field. a. True b. False90. Slip is the percentage difference between the speed of the rotor and the speed of the rotating magnetic field. a. True b. False 91. Synchronous motors are used to accommodate large loads and to improve the power factor of transformers in large industrial complexes. a. True b. false92. Transformers are constructed so that their characteristics match the application for which they are intended a. True b. False 93. Electronics or power transformers are sometimes considered to be those with ratings of volt-amperes and below. a. 100 b. 200 c. 300 d. 400 94. Effective voltage is equal to times the peak voltage. a. 0.636 b. 0.707 c. 6.036 d. 7.070 95. Some commonly used methods of cooling distribution transformers are using oil or some other heat-conducting material. a. True b. False 96. The auto transformer is generally used in low power applications where a variable current is required. a. True b. False 97. Average voltage is equal to times the peak voltage. a. 6.036 b. 0.707 c. 0.636 d. 7.070 98. Current lags voltage in a purely inductive circuit by a 90° phase angle. a. True b. False99. Copper loss is power lost in the primary and secondary windings of a transformer due to the ohmic resistance of the windings. a. True b. False 100. The voltage of a shunt-wound DC generator increase with an increase in load current. a. True b. False Loading…