QUESTION BANK : ELECTRICAL FUNDAMENTALSElectron Theory1. Pressure is used to produce voltage, this is1. piezo electric effect2. thermal electric effect3. static electric4. all2. Materials have more than half of valence electrons (Eismin, Pg 2)1. conductors2.insulators3. semi-conductors3. Element can be divided by (Eismin,Pg 2)1. hammering2.nuclear disintegration3. heating4.all4. If we increase the dis of two charged bodies from 2 millimeters to 5 meters force between them1. 6.25 x 106times less2. 6.25 x 106times more3. coulomb law will not act4. same5. Substances composed of only one type of atom are called (FA-9A/267)1. Molecule2.elements3. Compound4. none6. Hydrogen, oxygen, copper are the (FA-9A/267)1. compounds2.elements3. only gases4. all7. Electrical conductivity of a metal is due to (Grob-19/20)1. free electrons2. free protons3. holes4. ions8. In practice earth is choosen as a place of zero electric potential because it :- (SOURCE-INTERNET)1. Is non conducting2. Is easily available3. Keeps loosing or gaining electric charges every day4. Has almost constant zero potential9. Pure metals generally have - BLT1. high conductivity and positive temperature coefficient2. high conductivity and large temperature coefficient3. low conductivity and zero temperature coefficient4. low conductivity and high temperature coefficient.Static Electricity and Conduction10. Unit of conductance is1. Mho2. Kappa-13.Ohm4.all11. Static electricity can be generated by:(9A, P-269)1. friction2. contact3. induction4. all the above12. One Coulomb charge contains (Grob/24/25)1. 6.25 x 1019electrons2. 6.25 x 1018electrons3. 6.25 x 1017electrons 4. 6.25 x 1021electrons13. The force between two stationary charged particles is ____ force (BLT)1

1. electromotive2. electrostatic3. magneto motive4. centripetal14. If three coulombs of electricity flow through a conductor in three seconds the current is (Grob/31)1. one ampere2. one half ampere3. six ampere4. one third ampere15. Ampere /second could be the unit of (BLT)1. e.m.f.2. charge3. power4. energy16. Field of force existing around a charged body is:(9A, P-269)1. electrostatic field2. electro magnetic field3. atomic field4. none of the above17. First law of electro statics state that -1. Like charges repel each other2. Like charges attract each other3. Unlike charges attract each other4. Both 1 and 3 are correct18. Second law of electrostatic deal with - (B.L Thereja 190)1. Charge2. Force3. Distance between two charge body4 all of the aboveDC Sources of Electricity-19. Red lead paste is done in (Eismin, Pg 36)1. anode2.cathode3.both4.only on anode20.Expander which is used in Lead acid cell is (Eismin, Pg 36)1. Graphite2.Ground carbon3.Lampblack4.All are correct21. 4 cells of 2.0,15 amp hr, 2 are in series and 2 are in parallel, Now this arrangement is connected in series,output battery would be of1. 6 v 30 A A-H2.4 v 15 A-H3.6 v 15 A-H4.no battery can beformed22. Sealed type battery is also known as (Eismin, Pg-30)1. Re-combinant gas type2. Re-calibrated gas type3. Re-continued gas type4. all23. Oxygen gas is exerted at (Eismin , Pg 47)1. anode2.cathode3.both (a) and (b)4.no oxygen24. NiOOH remains at positive plate of Ni-cd (Eismin, Pg 49)1. charged condition2.during discharged condition3. no Ni oxyhydroxide forms4.all are correct25. all are correct14. The output voltage of a lead-acid cell is about: (BLT Electronics, P-84.1. 1.52. 2.23. 1.254. 626. During removal of battery from the a/c ____ terminal is disconnected at last in order to avoid ______ shortEismin/53.1. negative, accidental2. positive, accidental3. either negative or positive, accidental 4. none of the above is done2

27. When cell is loaded, the terminal voltage (Grob/347)1. is less then emf of cell by I r drop2. is equal to cells emf3. is greater than emf by I r drop4. all of the above are correct28. Sulphation in cell means (9A/309)1. to charge the cell at slow rate2. to discharge it at slow rate3. sulphate layer of active material becomes hard and useless4. boiling of electrolyte29. Factors affecting the capacity of cell are (9A/311.1. rate of discharge or recharge2. no of plates area of plates3. density of electrolyte and active material mass4. all of the above30. Ni / Cad cell is advantageous over Pb-acid cell from _____ point of view (9A/313.1. low maintenance cost and long service life2. short recharge time and good reliability3. excellent reliability and good starting ability4. all of the above31. In case of discharge of lead acid battery (Grob/354.1. formation of PbSO4on both plates occurs2. specific gravity of electrolyte increases3. cell emf. Increases4. colour of positive plates becomes chocolate deep brown.32. The negative terminal of a battery means it has ---- (Grob, 3A6)1. excess of electrons. 2. excess of protons3. deficiency of electrons 4. all of the above33. ____ is one of the factor of thermal run away of Nickel/Cadmium cell(Eismin/47)1. damaged layer of cellophane material 2. exothermic reactions at electrodes plates3. 30% of dilute KOH by volume4. both 1 & 234. The current delivering capacity of a cell depends on: (9A)1. condition of the electrolyte2. specific gravity of electrolyte3. physical size of electrode4. all the above35. Which of the following is a dry but rechargeable cell: Electronics, P-84.1. nickel-cadmium cell2. mercury cell3. lead-acid cell4. solar cell36. Rating of a battery is usually expressed in: (BLT Electronics, P-84.1. watt-hour2. joule3. ampere-hour4. amperes37 Which method is used to rapidly charge the battery: (Eismin-P-42.1. Constant current and varying voltage method2. Varying voltage and varying current method3. Constant voltage and varying current method4. none38. Vicious cycle occurs in: (Eismin-P-47)1. Generator2. Battery3. Motor4. Transformer39 Sulphation in lead acid battery occurs due to: (BLT1991-P-361.1. Trickle charging2. Heavy discharging3. Incomplete charging4. Fast charging40 Vicious cycle is another name of: (Eismin-P-47)1. Heavy discharge cycle2. Thermal runaway3. Heavy charging cycle4. None of the above3 41. Porous separators are used in a lead acid battery to:(9A,P-308)1. keep +ve & -ve plates from touching & shorting each other2. to allow electrolyte to circulate freely around plates3. safeguard +ve plate from distortion4. all the above42. Construction of vertical ribs on separators permits: (9A,P-308)1. free circulation of electrolyte around plates2. provides a path for sediment to settle to the bottom of cell3. both (a) and (b)4. none of the above43. Storage battery can be charged with: (9A,P-313.1. constant voltage2. constant current3. constant frequency4. both (1) and (2)44. In case Ni-cad electrolyte spills on body parts, should be rinsed with: (9A,P-314.1. vinegar2. lemon juice3. boric acid solution4. all the above45. Ni-Cd is preferred to lead acid battery as it has: (Ref. FAA 9A, Pg. 313.1. Short recharge time2. Excellent reliability3. Good starting capability4. All46. In lead acid battery (discharged state) negative plate used is:(Ref. FAA 9A, Pg. 313.1. Pb022. Pb SO43. Ni (OH)24. Cd (OH)247. In case of Ni/Cd battery, during discharge _____ remains unchanged (Eismin/47)1. voltage of cell2. specific gravity3. amount of active material at cathodes4. amount of active material at positive plate48. During the installation of battery in a/c, ___ terminal is connected first and in order to ___ (Eismin, 53.1. positive, complete the circuit2. negative, complete the circuit3. positive, avoid the accidental short4. negative, avoid the accidental short49. The capacity of a lead acid cell depends on (9A/310)1. temperature2. quantity of active material3. rate of discharge4. all of the above50 Nickel-cadmium batteries which are stored for a long period of time will show a low liquid level because(9A/314, Eismin -50)1. Electrolyte evaporates through the vents2. of current package form individual cells3. Electrolyte becomes absorbed into the plates4. None of these51. What may result if water is added to nickel cadmium battery when it is not fully charged ?(9A/314, Eismin 40)1. Excessive electrolyte deletion2. Excessive spillage is likely to occur during the charging cycle3. No adverse effects since water may be added any time4. None of these52. In a constant current charging system, a battery requires attention at the end of charge to avoid(9A/312, Eismin 42.1. Sulphation of battery 2. Spilling of electrolyte3. Evaporation of electrolyte4. Danger of overheating4 53. Active elements in a lead acid battery - (Eismin /35)1. nickel hydrate and iron oxide2. lead peroxide and spongy lead3. manganese dioxide and carbon 4. spongy lead54. Electrolyte used in lead acid battery is (Eismin /35)1. dilute sulphuric acid2. caustic potash3. nitric acid4. none55. When the temperature is increased, specific gravity of electrolyte (Eismin /41.1. increases2. decreases3. remains same4. none56. The capacity of a battery is expressed in (Eismin /44.1. ampere hour2. ampere volt3. percentage4. volts57. While testing the specific gravity of the electrolyte of a nickel cadmium battery, it shows a reading of 1.300,that means (9A /31A)1. the battery is fully charged 2. the battery is moderately charged3. the battery has lesser charge4. the charging state can't be predicted58. Hydrogen will be released at __ plates and oxygen will be released at ____ plates of a Ni-Cd battery(Eismin/49)1. negative, positive2. negative at charging & positive at discharging3. positive, negative4. positive at discharging) & negative at charging)59. When a battery is connected to a charger, which way should the connection be made: (Dale Crane, P-23.1. positive of the charger to the positive of the battery2. positive of the charger to the negative of the battery3. it really does not make any difference4. none of the above60. What characteristics of a lead acid battery determines its ampere hour capacity: (Dale Crane, P-23.1. the numbers of cells in the battery2. the area of the plates3. the density of electrolyte4. the internal resistance of the battery61. How can you tell when a battery on constant current charge is fully charged: (Dale Crane, P-23.1. the specific gravity doesnt show any increase in three consecutive readings taken one hour apart2. all of the cell are gassing freely3. both of the above conditions4. the battery voltage stops rising62. The state of charge of Ni-Cd battery can be found out by :- (CAIP-2- P-11.7)1. Open circuit voltage2. Amount of gassing3. Measured discharge test4. Specific gravity63. Ni-cd battery when connected for charging the gassing indicates: (Pallet-P-23.1. Battery is receiving proper charge and should continue charging2. End of charge and beginning of overcharging3. Beginning of charge and should be charged at the rate prescribed4. None of the these64. Two primary cells of 12 V and capacity 60 AH connected in parallel: (Grob-P-360)1. V= 24V. cap 60 AH2. V= 12V. cap 60 AH3. V= 12V. cap 120 AH65. In ni-cd battery electrolyte is spilled in eyes what should be used: (changing precautions)5 1. Baking soda2. Water dilute Solution of boric acid3. Plenty of water4. Soda bi carbonate66. Negative plate of a ni-cd battery is made of: (Eismin-P-49)1. Metallic cd2. Cd hydroxide3. Ni hydroxide 4. Nickel67. MTCS regarding mixing of the electrolyte for lead acid battery: (Dale Crane, P-51.1. the electrolyte that is furnished with a dry charged battery must be mixed with enough distilled water to adjust itsspecific gravity to 1.8352. be sure to pour the acid into water never vice versa3. be sure to pour the water into acid never vice versa4. pure concentrated sulphuric acid is used as an electrolyte it does not need to be mixed68. What is the specific gravity of fully charged lead acid battery (Dale Crane, P-23.1. 1.260 to 1.285 at 800F2. 1.260 to 1.28 at 1000F3. 1.835 at 800F4. 1.150 at 800F69. In a nickel cadmium battery when is the electrolyte level is highest: (Dale Crane, P-8)1. immediately after the battery has completed its charge2. after the battery has been fully charged and allowed to rest for an hour or two3. the electrolyte level does not change in a ni-cad battery70. What is the function of the electrolyte in a nickel cadmium battery (Dale Crane, P-23.1. serves as an active element in the chemical action generating the current2. serves as a conductor only, and does not take part in the chemical action3. serves only to keep the cell cool4. serves as an indicator of the charge of the cell71. How can you tell when a constant voltage charge of a nickel-cadmium battery is complete: (Dale Crane, P-23.1. the voltage stop rising2. the current decreases and stabilized3. the specific gravity of electrolyte rise to 1.3004. the cell voltage rises to 1.82 volts per cell72. What type of battery charger is recommended for the final charge of nickel cadmium battery: (Dale Crane, P-24.1. constant current charger2. constant voltage charger3. a/c gen. charging system in the airplane4. charger which puts a low voltage alternating current across the battery73. What may be used to neutralize spilled electrolyte from a nickel cadmium battery: (Dale Crane, P-24.1. baking soda 2. ammonia3. triehlorothene4. vinegar74. Fact relating to secondary cell is that: (Eismin P-31.1. active material does not go into solution2. it can be recharged and discharged many times before complete deterioration3. active material undergoes chemical change during charging and discharging4. all of the above are correct75. One more negative plate in Pb-acid cell than positive plates is used in order to: (BLT Vol , P-353.1. prevent positive plate from warping or buckling2. increase the cell potential3. increase the cell capacity4. decreases the cells internal resistance76. In case of ni-cad battery, during discharge remains uncharged:(Eismin, P-47)6 1. voltage of cell2. specific gravity3. amount of active material at cathodes4. amount of active material at positive plate77. In the a/c, storage battery is charged by: (Eismin P-47)1. constant DC current2. constant DC voltage3. constant AC voltage 4. constant AC current78. The specific gravity of electrolyte is measured by hydrometer. The correction of specific gravity is required at:(Eismin, P-41.1. every time2. when temperature is above or below 800F3. when the temperature is above or below 600F4. when the temperature exceeds 1400F79. The e.m.f. of a battery is: (Eismin, P-43.1. less than terminal voltage2. equals terminal voltage3. greater than the terminal voltage4. less or more depends on direction of current flow80. In different countries, the same rate of battery was charged, which gets more charge: (Eismin, P-41.1. 00F, 1hr2. 800F, 1hr3. 600F, 1hr4. 700F, 1 hr81. A fully charged lead acid battery will not freeze until extremely low temperatures are reached because: (Eismin,P-39)1. the acid is in the plates, thereby increasing the specific gravity of the solution2. most of the acid is in the solution3. increased internal resistance generates sufficient heat to prevent freezing4. none of the above82. What determines the amount of current which will flow through a battery will be able to charged by a constantvoltage source: (Eismin, P-62.1. the total plate area of the battery2. the state of charge of the battery3. the ampere hour capacity of the battery4. any of the above83. In nickel cadmium battery, rise in cell temperature: (Eismin, P-47)1. causes an increase in internal resistance2. causes a decrease in internal resistance3. increases cell voltage4. none84. In a constant current charging system a battery requires attention at the end of charge to avoid:(Eismin, P-47)1. sulphation of battery2. spilling of electrolyte3. evaporation of electrolyte4. danger of over charging85. Electrolyte solution in ni-cad battery is: (Eismin, P-47)1. 70% KOH & 30% of distilled water by weight2. 30% KOH & 70% of distilled water by weight3. 70% KOH & 30% of distilled water by volume4. 30% KOH & 70% of distilled water by volume86. The separators used for ni-cad battery is: (Eismin, P-47)1. cedar wool7 2. woven nylon fabric with a cellophone layer3. micro porous plastic with cellophone layer4. glass wool mixed with cellophone87. Nickel-cadmium battery: (Eismin, P-52.1. stored in only charged condition2. can be stored in discharged condition for longtime3. reduces capacity if stored in Hot condition4. none88. What is the neutralizing agent to be applied on skin when acid falls on it?(9A)1. Potassium Hydroxide2. Sodium Bicarbonate3. Boric powder89. Which of the following is correct for the Ni/ Cd battery (Eismin/46)1. current delivering capacity less2. it can not be discharged to zero voltage level3. for same capacity of pb acid, its weight is high4. its initial cost is relatively high90. Horizontal ribs in Pb-acid cells (9A/308)1. provide the cavity for fallen material2. provide the cavity for electrolyte3. enhance the rate of reaction4. enhance the delivering rate of current91 High rate of discharge in relation to battery means - (Eismin/50)1. charging the battery at a very high rate2. discharging the battery by employing a heavy load3. discharging the battery by shorting the terminals4. all are correct92. What may result if water is added to nickel cadmium battery when it is not fully charged ? 9A/314, Eismin-40)1. S.G of electrolyte decreases2. Excessive spillage is likely to occur during the charging cycle3. No adverse effects since water may be added any time4. None of these93 Battery is a source that - (Eismin/30)1. generates emf by chemical action2. converts mechanical energy into electrical energy3. converts heat energy into electrical energy4. None94. Electrolyte used in NI-CAD battery is (Eismin/35)1. 30% sulphuric acid + 70% water2. caustic potash3. nitric acid4. none95. During discharge of a lead acid battery, voltage of cell (9A/310)1. decreases2. increases3. remains constant4. none96. While testing the specific gravity of the electrolyte of a nickel cadmium battery, it shows a reading of 1.300,that means (9A /31A)1. the battery is fully charged2. the charging state can't be predicted3. the battery is moderately charged4. the battery has lesser charge8 97. The purpose of providing bottom grooves underneath the plates in a lead acid cell container is to (Eismin/37)1. allow for convection of the electrolyte for cooling of the plates2. ensure that the electrolyte's quantity and plate area is adequate3. prevent sediment build up from contacting the plates and causing a short circuit4. prevent escape of electrolyte but allow98. The separators used in lead acid battery have vertical ribs on the side (Eismin/37)1. facing the positive plate2. facing both the positive & negative plate3. facing the negative plate4. half part facing positive plate & half part facing negative plateDC Circuits99. Ohms law is applicable to (Eismin/13-14.1. ac circuits only2. dc circuits only3. both, ac & dc circuits4. none of these100. Kirchhoffs laws are applicable to ________ (Eismin 26-27)1. Sinusoidal voltage only2. d.c. voltage only3. Voltage of any wave shape4. none of the above101. Kirchhoffs voltage law is concerned with ______ (Eismin/26-27)1. IR drops2. battery emf.3. Junction voltage4. both 1 & 2.102. In a Wheatstone bridge, the current through the galvanometer at balanced condition is _______.(Grob/177)1. 1.08 A2. 0.0A3. 1.414 A4. 1.732 A103. For a fixed supply voltage, the current flowing through a conductor will increase when its:(Ref. FAA 9A, Pg. 283.1. Area of cross-section is reduced2. Length is reduced3. Length is increased4. Length is increased & cross sectional area is reduced104. Specific resistance of a conductor depends:FAA 9A1. Dimensions of the conductor2. Composition of conductor material3. Resistance of the conductor4. All of the above105. Which of the following materials possesses the least specific resistance (Ref. FAA 9A, Pg. 273.1. Aluminum2. Copper3. Silver4. Iron106. In a series circuit:(Ref. FAA 9A, Pg. 206)1. Current flowing through each resistor is same2. Resistors are additive3. Applied voltage is equal to sum of voltage drops across individual resistors4. All of the above107. Wheatstone bridge is useful for measuring ____. (Grob/172.1. Very high resistance2. Very low resistance3. Medium range resistance 1to 100 k4. None of the above108. Kirchhoffs laws are applicable to (Grob 258-269)1. ac2. dc3. both 1 & 24. none of the above9

109. Kirchhoff's current law is applicable to(Grob/258)1. closed loops in a network2. electronic circuits3. junction in a electric network4. electric circuits110. For doubling the current in a circuit of a constant resistance, the applied voltage must be: (BLT , P-9)1. kept squared2. doubled3. halved4. quadrupled111. The polarity sign of an IR drop is primarily dependent upon (Grob/259)1. amount of current flowing through it2. value of R3. direction of current flow4. battery connection112. In a circuit the voltage is doubled and the resistance is cut in half at the same time the current will be(9A/273 & Ohms laws)1. doubled2. a quarter3. a half4. four times as high113. In a parallel circuit, all component must (Grob, 132.1. have the same potential difference across them2. have same value3. carry equal current4. all114. Four 1.5V cells are connected in parallel. The output voltage is (9A, 276)1. 1.0V2. 1.5V3. 6.0V4. None115. Which of the following statement is true both for a series and a parallel dc circuit? (Grob /164.1. powers are additive2. voltages are additive3. currents are additive 4. elements have individual currentsResistance / Resistor-116. A good electric conductor is one that (BLT)1. has low conductance2. is always made of copper wire3. produces a minimum voltage drop4. has few free electrons117. cylindrical wire, 1 m in length, has a resistance of 100 ohm. What would be the resistance of a wire made fromthe same material if both the length & cross-sectional area are doubled? (9A/273.1. 200 ohms 2. 400 ohms3. 100 ohms4. 50 ohms118. Factors affecting the resistance value is (9A/273.1. cross sectional area 2. Length3. Temperature4. All119. Ideal Constant voltage source has ____ internal resistance while practical constant currentsource has ___ internal resistance. (Grob, 375)1. zero, very high2. very low, very high 3. very low, infinity4. zero, infinity120. A linear resistor is defined as a resistor: (BLT Electronics, P-10)1. whose value is independent of applied voltage2. whose V-I characteristics is a straight line3. whose current varies inversely with the applied voltage4. both 1 and 2121. If current through a resistor is halved, wattage developed by it would be: (BLT Electronics, P-74.1. halved2. quadrupled3. cut to one-fourth4. doubled122. The colour of the fourth band of the carbon resistor indicates its (Grob/53.10

1. current rating 2. Ohmic value3. voltage rating4. tolerance123. In a resistance, coded as per end-to-centre system of marking, if the third band is silver in colour, the first twodigits must be - (9A/280)1. multiplied by 10%2. multiplied by 1%3. divided by 10%4. divided by 1 %124. Which of the following will cause the resistance of a conductor to decrease ? (9A/273.1. increase the length or decrease the cross-sectional area2. decrease the length or increase the cross sectional area3. decrease the length or the cross sectional area4. increase the length or the cross sectional area125. Resistance of a wire is 4 ohms and is stretched to twice its length. The resistance now is (Grob/50,51,52.1. 4 ohms 2. 8 ohms 3. 12 ohms4. 16 ohms126. Carbon composition resistors are most popular because they (9A/352.1. cost the least2. are smaller in size3. can withstand over loads 4. do not produce electric noise127. Current and voltage in an a.c. resistive circuit are (9A/352.1. 900out of phase2. in phase3. 900out of phase current leading voltage4. 1800out of phase.128. The % tolerance for gold is (Grob/53,54.1. 5%2. 2%3. 10%4. 20%129. In end-to- centre colour coding of resistance, if the colours are brown, black, red the value of resistance is(9A/352.1. 1002. 1000 k3. 104. 1 k130. A unique feature of wire wound resistor is its (Grob /57)1. low power rating2. very high stability3. low cost 4. smaller size131. The condition for ohm's law is related to (Eismin/13.1. the temperature should remain constant2. ratio V/I should be constant3. the temperature should vary4. current should be proportional to voltage132. If a 12 volt circuit furnishes 3 amperes to a parallel circuit consisting of three equal resistors, what is the valueof each individual resistor ? (Self made questions, Ohm laws)1. 12 ohms2. 4 ohms3. 1.33 ohms 4. cannot be determined133. Precision value resistance is composed of:-(GROB)1. Copper 2. Gold 3. Carbon4. Manganin134. Carbon composition resisters are most popular because they : (BLT Vol-I, P-49)1. cost least2. are smaller in size3. can withstand over loads4. both (a) and (b)135. if there is no forth color band on the resistor, the tolerance is to be understood as: (9A, P-280)1. 10%2. 20%3. 5 % 4. no tolerance136. MTCS Rheostat has:(9A,P-296)1. three terminals and controls current1. two terminals and controls voltage3. three terminals and controls voltage4. two terminals and controls current11 137. MTCS A potentiometer has:(9A,P-296)1. two terminals and controls voltage2. three terminals and controls current3. two terminals and controls current4. three terminals and controls voltage138 The Current Voltage equation will be[FAA 9A, P-290]1. IR1+ IR2+ IR3= E1-E2+E32. I(R1+ R2+ R3) = E2-E1+E33. I(R1+ R2+ R3) = E3-E1E24. IR1+ IR2+ IR3= E1+E2E3Power139. The ratio of resistances of a 100 Watt, 220 V lamp to that of a 100 Watt, 110 V lamp will be, at therespective voltages (Ohms law)1. 4:12. 2:13. 1:24. 1:4140. A voltage drop is 100 volt across a 100 ohms resistance delivers (9A/284.1.10,000 watts2.1000 watts3.100 watts4.10 ampere141. A 200 W, 230 V lamp is connected across 115 V supply. The lamp will draw power (Ohms law)1. slightly more than 50 watts2. slightly less than 50 watts3. exactly 100 watts4. exactly 50 watts142. When adding a rheostat to a light circuit to control the light intensity, it should be connected (9A/296)1. in parallel with the light2. across the source of energy3. in series with the light4. in series-parallel with the light switchCapacitance / Capacitor143. The equivalent capacitance value, when three capacitor having same value, are connected in series, is(Eismin/10A)1. 75 micro farad2. 25 micro farad3. one third of each value4. three times the value of the capacitor144. The charge of electricity that can be placed on capacitor is proportional to - (9A/350)1. applied voltage and frequency 2. capacitance and frequency3. applied voltage and capacitance4. capacitive reactance145. The working voltage of a capacitor in an a.c circuit should be (9A/351.1. equal to the highest applied voltage2. at least 20% greater than the highest applied voltage3. at least 50% greater than the highest applied voltage4. none of these146. Capacitors are used to (Eismin/105)1. block a.c. and pass d.c.2. block dc and pass ac3. pass a.c. and d.c. 4. block a.c. and d.c.147. The dielectric strength is measured in terms of (9A/351.1. breakdown voltage per unit thickness2. breakdown voltage12 R3 R1E2R2E3I

3. current4. watt148. In one time constant, capacitor takes the charge up to ___ % of its full charge (Eismin/105)1. 63.22. 36.73. 20.6 4. 80.2149. Net power consumed by pure inductor or capacitor is _______ (BLT)1. 2 watt2. zero3. 6 watt4. none of these.150. A capacitor has energy which is given by(9A)1. CV22. I2R3. V2/R4. none of the above151. Coulomb per volt is the unit of (Grob/493,495,496)1. inductance2. inductive reactance3. capacitance4.capacitive reactance152. Which of these items does not enter into determination of the capacity of a capacitor: (BLT , P-5.1. thickness of the dielectric2. material of which the plates are made3. material of which the dielectric is made4. area of the plates153. The capacitive reactance decreases as the value of the capacitance increases because a large capacity capacitorwill (9A/352.1. take less charge than low capacity capacitor2. take greater charge than low capacity capacitor3. require lower voltage than low capacity capacitor4. require higher voltage than low capacity capacitor154. When relatively high capacitance is required in a small capacitor we use (GROB-P- 503.1. Ceramic capacitor2. Paper capacitor3. Electrolytic capacitor4. Mica capacitor155. When the capacitor is charged fully the value of the current in the circuit is: (Grob-P-338)1. Zero2. Maximum3. Minimum4. Moderate156. The energy stored in a capacitor depends on:(GROB)1. directly proportional To the area plate2. inversely proportional to the distance between the plates3. depends on dielectric4. all of the above157. The dielectric used in variable capacitor is: 9A1. mica2. paper3. air4. oil158. The working voltage of capacitor depends on (9A/351.1. frequency of voltage2. thickness of dielectric3. type of dielectric4. all of the above159. There is a greater possibility of voltage breakdown and leakage current in an electrolytic capacitorbecause (9A/349)1. the electrolyte used is in a liquid or a paste form2. the electrolyte is having a low dielectric strength3. dielectric is a thin film of oxide4. undesirable low frequency160. Capacitors are said to: (Eismin- 106)1. block AC and pass DC13 2. block DC and pass AC3. pass AC and DC both4. block AC and DC both161. How many time constant needed by a capacitor to be charged upto 99.8%: (Eismin, P-105)1. 062. 043. 074. 05Magnetism-162. Whenever a magnet is quickly brought towards an open circuited stationary coil (Grob/425)1. a current is induced in it2. work has to be done3. e.m.f. is induced in it4. power is spent163. Magnetism of a magnetic can be destroyed by (Grob/393.1. heating2. inductive action by other field3. hammering4. all of the above164. Permanent magnets are normally made of (Grob/388)1. aluminium2. wrought iron 3. cast iron4. alnico alloys165. In a magnetic material, hysteresis loss takes place primarily due to (Grob/406)1. flux density lagging behind magnetizing force2. molecular friction3. its high retentivity4. rapid reversals of its magnetization166. Soft magnetic materials have (Grob/403.1. high permeability & low coercive force2. low permeability & high coercive force3. high residual magnetism4. low resistivity167. The property of a material which opposes the production of magnetic flux in it is known as (Grob/409)1. mmf2. reluctance3. permeance4. permittivity168. The retentivity of magnetic material means (BLT/318)1. residual magnetism2. ability to remove the residual magnetism3. ability to keep residual magnetism4. ability to get magnetism169. The soft iron piece is used as electromagnet because it has __ retentivity and ____ permeability(Jeppesen)1. low, high2. low, low3. high, low4. high, highInductance / Inductor170. Inductance of a coil is determined by the(Jeppesen 3-51.1. type of core2. number of turns3. shape and size of the coil4. all of the above171. Inductive reactance is measured in (Jeppesen 3-53.1. Henrys 2. Gilbert3. Ohms4. Farads172. XLincreases with increase in both (Jeppesen 3-53.1. f & c2. f & L3. R & P4. all of the above173. Direction of the induced emf in a generator is determined by generator (Jeppesen 4-2.1. left hand rule2. right hand rule14

3. both hand rule4. none of these174. A coil has an inductance of 1H if current is changing at the rate of 2 Ampere/sec induces:(BLT Electronics, P-74.1. one volt in it2. two volts in another coil3. two volts in it4. half a volt in it175. According to lenzs law, the emf induced in a coil always . the cause: (9A-344.1. assist2. opposes3. equate4. none176. When a coil carrying current produces magnetic field the field is(Eismin-P-9 & Grob-P-422.1. Concentrated at the centre of coil2. Spreads equally in the coil3. Concentrated at the surface of length4. None of the above177. Higher the self induction of a coil (Grob/577)1. lower the emf. Induced in it2. longer is the delay in establishing steady current through it3. greater the flux produced by it4. lesser the weber turns178. The field at any point on the axis of a current carrying coil will be (BLT/264.1. perpendicular to the axis2. parallel to the axis3. at an angle of 45 degree with the axis4. zero179. The force required to wipe out the residual magnetism is called (Grob/408)1. retentivity2. magnetizing force3. coerceive force4. permeability180. For a given shape of a coil, the amount of inductance depends on (BLT)1. no. of turns 2. core3. separation between the turns4. all of these181. If a magnetic material is used as the core of inductor, the property of material (Grob/579)1. decreases the inductive reactance2. increases the permeability of coil3. increases the inductance of the coil4. decreases the inductance of the coil182. Four inductor of 2H is connected in series is the equivalent inductance (Grob/603.1. 2 h2. 1/2 H3. 8H4. None183. A coil with a certain number of turns has a specified time constant. If the number of turns is doubled,its time constant would (Eismin/107)1. remain unaffected2. becomes doubled3. becomes one fourth4. get halvedDC Motor / Generator Theory184. The dynamically induced emf. in a conductor does not depend on (self made)1. its conductivity2. flux density3. the active length4. its velocity185. The induced emf when a conductor moves along the magnetic axis with very high speed is(Grob/425/488/489)1. maximum depending on different factors2. zero because cutting flux is maximum3. zero because rate of cutting of flux is negligible4. some value186. An emf. is induced in a conductor whenever it (Grob/429)15

1. lies in a magnetic field2. cuts magnetic flux3. moves parallel to the direction of the magnetic field4. lies perpendicular to the magnetic flux187. In elementary d.c. generator, if no of coil is increased (Pallette/2.1. induced emf. will increase2. no. of ripple frequency will increase, resulting in steady dc3. ripple will decrease4. both 2. and 3.188. Which of the following facts related to elementary d.c. generator is incorrect? (9A/297)1. during the rotation, for instant, when coil's plane remains along MNA induced emf is minimum2. in above case, when coil's plane is along magnetic neutral axis (MNA), induced emf is maximum3. direction of current flow in coil direction of polarity of induced emf is given by Fleming left hand rule189. In a self excited dc-generator, electromagnet instead of permanent magnet is used for necessary field(BLT)1. to change the field strength as per requirement2. because with time strength of a magnet decreases3. because its size is less4. all of the above190. In generator, induced emf depends on (BLT/302.1. no. of turns2. field strength 3. speed of armature4. all of the above191. In dc motors (9A/447/448)1. net emf = applied voltage - counter emf2. net emf = counter emf - applied emf3. net emf = counter emf 4. net emf = applied voltage192. Degree of compounding means the effect of ___ on ___ (BLT)1. series field, terminal voltage2. terminal voltage, series field3. generated voltage, terminal voltage4. shunt field, series field193. If the terminal voltage is equal to no load voltage, generator is called 9A/396)1.flat compound2. cumulatively compound3. differentially compound4. either 2 or 3194. In compound wound generators _____ field coil is of ____ conductor with ____ turns. (9A/396)1. series, thick, a few2. series, thin, many3. series, thin, a few4. series, thick, many195. The effect of armature reaction may result in (9A/397)1. pitted commutator surface2. reduction in output voltage3. enough wear on brushes4. all of the above196. The ____ motor is not started without mechanical load (9A/445/446)1. d.c. series2. shaded pole3. induction 4. capacitor start197. The part of a d.c. motor which changes the current flow from one wire to another is (9A/392.1. yoke2. brushes 3. armature4. commutator198. The field poles and armature in a d.c. generator are laminated in order to reduce its (9A/391.1. weight 2. speed3. eddy current loss4. hystresis loss16 199. In d.c. generators, armature reaction is produced actually by (9A/397)1. its field current 2. armature conductors3. field pole winding4. load current in armature200. If residual magnetism of a shunt generator is destroyed accidentally, it may be restored by connecting its shuntfield (9A/39A)1. to earth2. to an a.c. source3. to a d.c. source4. either 2 or 3201. A large series motor is never started without some mechanical load on it because (BLT)1. draw too much current2. develop excessive speed and damage itself3. produce vicious sparking at brushes4. open fuse or circuit breaker202. Which generator is used when voltage is of prime importance ? (BLT)1. series wound 2. shunt wound3. compound wound4. both 2 and 3203. If a short circuit occurs between the positive armature lead and the field lead of a shunt generator which has thevoltage regulator located in the positive side of the field circuit the -1. generator voltage will drop to zero2. generator will only produce residual voltage3. reverse current cut out relay will open and remain open until the fault is corrected4. generator voltage will increase204. Generator inter poles: (Pallette/4.1. Improve generator output 2. Prolong the life of the brushes & commutator3. Reduces radio interference4. All of the above205. Iron loss is the combination of : (BLT/1168)1. Copper and eddy current loss2. Hysterisis and Eddy current loss3. Copper & Hysterisis loss4. Copper & Mechanical loss206. A dc series motor is started on no load its speed is : (9A/445,446)1. zero 2. normal3. infinite4. none207. Which of the following motors gives a high starting torque. (BLT)1. series motor2. shunt motor3. compound motor4. none208. Why is the air gap between the yoke and armature of an electric motor kept smaller (BLT)1. to achieve a stronger magnetic field2. to avoid overheating of machine3. both 1. & 2.4. none209. Eddy current can be reduced by (BLT/1168)1. reducing the thickness of the conductor2. replacing the solid core with several insulated thin metal plates3. applying high frequency a.c.4. simply using a mica layer between coil & core210. Which one of the following generator is not used in a/c power generation system? (BLT)1. shunt wound generator2. series wound generator3. compound wound generator211. When a current carrying conductor is placed in a magnetic field, it tends to rotate this principle is used in(BLT)1. generator2. motor3. hotwire instrument 4. rectifier212. When heavy starting torque is required, we use (BLT)1. compound wound 2. shunt wound motor17 3. series wound motor4. d.c. motor213. In a DC generator ripple can be reduced by adding (Jeppesen 4-4.1. more loop2. less loop3. more resistance4. none of these214. The brushes connected with commutator is placed (9A/397)1. 90 away from its neutral position 2. 180 away from its neutral position3. in neutral position4. 270 away from its neutral position215. For a d.c. motor which of the following is wrong (BLT)1. copper losses in field and armature winding2. hysteresis losses in armature core3. hysteresis losses in electromagnet4. eddy current losses in magnetic core216. The armature reaction, in d.c. generators is produced actually by (9A/397)1. its field current 2. armature conductors3. field pole winding4. load current in armature217. The back emf. of a d.c motor (BLT)1. often exceeds the applied voltage2. aids the applied voltage3. helps in energy conversion4. regulates its armature voltage218. When a series motor is run without load, the speed may increase for above the normal speed, causing armatureto fly apart because (9A/394.1. at starting there is no counter emf2. counter emf is higher than the applied emf3. counter emf remain sufficiently below the applied emf4. applied emf remains sufficiently below the counter emf219. Under varying conditions of speed and load the only practical method of maintaining a constant voltage outputfrom an aircraft generator is to vary (9A/398)1. the strength of the magnetic field2. the number of conductors in the armature3. the speed at which the armature rotates4. the brush pressure on the commutator segments220. In a generator, what eliminates any possible sparking to the brush guides caused by the movement of thebrushes within the holder (FAA-9A)1. brush spring tension2. the brush pigtail3. undercutting the mica on the commutator4. lubricating the brush sides221. To what depth is the mica insulation between the commutator bars of a d.c. generator, undercut is (BLT)1. equal to the width of the mica2. one half the width of the mica3. equal to twice the width of the mica4. none222. The output of an elementary generator is represented by (Jeppesen 4-4)1. sine curve2. cos curve 3. parallel curve4. none of these223. The frame of a generator is (Jeppesen 4-5)1. high permeable2. low permeable3. Nill permeable4. all of the above18 224. Commutator is made of (Jeppesen 4-6)1. hard drawn copper segments2. soft drawn copper segment3. hard drawn anilco steel4. all of the above225. The raised portion of each commutator segment is called (Jeppesen 4-7)1. lowerer2. riser3. cut portion4. only 1 & 3226. The adverse effect of armature reaction is minimized by : (Eismin, P-194.1. shifting the brushes along the MNA2. placing the inter poles3. placing the compensating winding4. all are correct227. The effect of magnetic filed produced by current carrying armature conductors: (Eismin, P-194.1. reduction of effective filed strength2. distortion of field flux3. sparking on the commentator and brushes4. all are correct228. Long shunt compound wound generator have: (BLT-Vol-II-P-988)1. Series field across both armature and shunt field2. Shunt field across both armature and series field3. Shunt filed across armature only4. Shunt field in series with inter poles229. At no load a series D.C generator has e.m.f equal to : (General)1. Maximum of rated voltage2. Minimum of rated voltage3. Maximum of rated voltage + IR drop4. No induced e.m.f230. Self exited generator has: (BLT-Vol-II-P-982.1. Permanent magnet2. Separate 4.C source3. Electromagnetic coil which is magnetized by machines current itself4. All231. The main function of inter poles is to minimize______________ between the brushes and the commutatorwhen the 4.c machine is loaded: . (BLT-Vol-II-P-962.1. Friction2. Current3. Sparking4. Wear and tear232. The sole purpose of commutator in a d.c generator is:(BLT-VOL-II-P935)1. To increase out put voltage2. Reduce sparking at the brushes3. Provide smoother out put4. Convert the induced a.c into d.c233. Brush wear increase at: (Pallet-P-10)1. Low altitude2. Higher altitude3. In cloudy whether4. In summer234. How can the direction of rotation of a d.c. motor be changed ? (9A/448)1. interchange the wires which connect the motor to the external power source2. reverse the electrical connection to either the field or armature winding3. rotate the brush assembly by 90 degree4. remove the starting winding235. Which shunt wound motor is suitable for(BLT)1. operating landing gear 2. operating flaps & slats3. running gyro & servo actuators4. starting engine19 236. Which one is not related for determining the amount of voltage produced in generator (BLT)1. the number of magnetic lines of flux2. the number of conductors cutting the flux3. the size of the conductor cutting the flux4. the speed at which the conductor cuts the flux237. How does armature reaction cause brush arcing - (9A/397)1. it moves the neutral plane away from the brush location2. it decreases the spring pressure holding the brush into the commutator3. it increases the output voltage of the generator4. it decreases the current in the armature238. If load on a DC shunt motor is increased, its speed is decreased primarily due to : (Jeppssen P-131.1. increase in its flux2. decrease in back emf3. increase in armature current 4. increase in brush drop239. The commutation process in a d.c generator basically involves (9A/397)1. Passage of current from moving armature to a stationary2. Reversal of current in an armature coil as it crosses MNA3. both 1 & 24. none240. In motor right hand rule the direction of the torque is denoted by (FAA 9A)1. index finger2. middle finger3. thumb4. none of these241. In Generator left hand rule the direction of lines of magnetic flux is denoted by (Jeppesen)1. fore finger2. first finger3. index finger4. all of the above242. When the flow of electrons in two wires is opposite, the resulting magnetic fields forces the wires(Jeppesen 4-29)1. closer2. apart3. both 1 & 2 4. none of these243. The armature of a typical DC motor and DC generator is1. dissimilar2. similar3. not identical4. both 1 & 3244. To vary the speed of a shunt motor, a device used is (Jeppesen 4-31.1. transistor2. diode3. rheostat4. capacitor245. When field current of a motor is increased the motor speed will (Jeppesen 4-31.1. increase2. decrease3. remain same4. none of these246. The motor in which two field windings wound in opposite directions on the same pole to reverse the directionof rotation is known as (Jeppesen 4-32.1. shunt motor2. series motor3. same field motor4. split field motor247. When the current in field winding of series motor is increased then the current in armature winding will(Jeppesen 4-33.1. decrease2. increase3. remain same4. none of these248.. What is the relationship between the desired voltage regulator setting and the ambient temperature in whichthe airplane is operated: (Dale Crane, P-23.1. the colder the ambient temp, the lower the voltage should be set2. the colder the ambient temp, the higher the voltage regulator should be set20 3. ambient temp. has no bearing in the desired voltage of the charging system4. the regulated voltage should be same regardless of the temperature249. The brushes connected with commutator is placed (9A/397)1. 90 away from its neutral position2. 180 away from its neutral position3. 270 away from its neutral position4. in neutral position250. The speed of a dc motor can be controlled by varying (9A/449)1. field strength2.Armature circuit resistance3. Applied voltage4. All of the above251. The purpose of a growler test is to determine the presence of (Jeppesen)1. an improper capacitor2. a shorted armature3. a broken field frame 4. a broken voltage regulator connection252. Which one of the following parts is not essential for d.c. generator (9A/390/391.1. armature2. slip ring3. split ring 4. commutator253. In a type of DC generator, when load is increased, voltage increases and when the load is decreased, voltagealso decreases, the generator can be (9A/394.1. Shunt generator2. Differential compound generator3. Compound generator4. Series generator254. In a long shunt compound wound generator, the shunt field is connected in parallel with (9A/395)1. Armature2. Series field3. Parallel combination of armature and series field4. Series combination of armature and series field255. The __________ dc generator has the poorest voltage regulation (BLT)1. Over-compound2. compound3. Shunt4. Series256. Which of the following generator provides approximately constant voltage from no-load to full load (9A/396)1. Series 2. Shunt3. flat compound4. Over compound257. The armature torque of a dc motor is a function of its (9A/438)1. pole flux2. Armature current3. Speed4. Both 1 and 2258. The speed of a dc motor can be controlled by varying (9A/449)1. its flux2.Armature circuit resistance3. Applied voltage4. All of the above259. The level of compounding in a cumulatively-compound d.c. Generator is usually adjusted by (BLT)1. alternating series field current2. changing shunt field current3. connecting it long-shunt4. connecting it short - shunt260. An electric motor is used for (9A/438)1. Generating power 2. Changing mechanical energy to electrical3. changing electrical energy to mechanical4. increasing the energy put into it261. The commutator segments are insulated from one other by (9A/397)1. thin sheet of mica2. using riser3. hard drawn copper 4. pig tail262. The speed of series wound dc motors can be changed (BLT)21 1. by field diverter above normal value2. by field diverter below normal value3. either 1. and 2.4. none of the above263. Series dc motors are used in a/c (9A/446)1. as engine starter2. for raising or lowering landing gear3. for cow flaps4. all of the above264. In a d .c generator , the cause of rapid brush arcing may be (BLT)1. imperfect contact 2. severe sparking3. rough commutator surface4. any of the above265. The induced emf is max. if the conductor cuts the magnetic field at (9A/342.1. 002. 4503. 9004. none266. Series DC motor: LT-Vol-II-P-1015)1. Field winding made of few turns of heavy wire2. Poor voltage regulation3. Both 1 & 24. None of the above267. If a magnet is dropped through a current carrying coil it falls with: (Grob-P-581.1. Uniform acceleration equal to g2. Non uniform acceleration less than g3. Uniform acceleration less than g4. Uniform acceleration more than g268. The basic requirement of d.c generator armature winding is that it must be: (BLT-VOL-II-P935)1. A lap winding2.A closed one3. A wave winding4. Either 2 and 3269. The series field of a short shunt d.c generator is excited by _________current: (BLT-VOL-II-P936)1. Shunt2. Load3. Armature4. External270. The .. reverses the direction of current in generator or motor. [ISMIN, P-191]1.Commutator2. Bursh3. Slip ring4. commutator segment271. Which motor is operated by both AC or DC voltage ? [EISMIN, P-183]1. Repulsion2. Universal3. Split phase4. capacitor272. Compound motor is:(Ref. FAA 9A, Pg.447)1. Shunt2. Series3. Combination of both4. None273. Starting torque in case of the shaded pole motor is:(Ref. FAA 9A, Pg.455)1. Very Weak2. Power factor is low3. Both4. NoneAC Theory274. Power in any electrical circuit is1. additive2.substracted3. multiplied4. divided275. Power is calculated in terms of and depends on (Eismin, Pg 14)1. R,I,V2.Only V & I3.Only R & V4.Only I & R276. Wheatstone bridge in balanced condition1. shows zero deflection on Galvanometer22

2. all resistance will be constant3. two resistance will be out of circuit4. none of above277. The direction of an a.c current (Grob, AAA, AA5)1. keeps changing2. can not be found3. keeps reversing4. is fixed278. The effective voltage of a a.c. sine wave 200 peak-to-peak, is approximately (9A/343.1. 70.7 volt2. 141.4 volt3. 63.7 volt4. 127.4 volt279. The r.m.s value of a sine wave is equal to (9A/343.1. 0.637 X max. value2. 0.707 X max. value3. 0.506 X max. value4. 1.414 X max. value280. When current passes through a conductor, the resultant effect is (BLT)1. a magnetic field is produced2. magnetic as well as heating effect3. only heating effect 4. only chemical effect281. In aircraft, frequency of a.c. supply is (FAA-9A)1. 800 Hz2. 400 Hz3. 200 Hz4. 100 Hz282. The time period of a sine wave of frequency 50 Hz. is ______ seconds.(Grob/452.1. 0.022. 0.033. 0.044. 0.05283. A sinusoidal ac voltage which undergoes 100 reversals of polarity per second has a frequency of ___ Hz.(Grob/455)1. 502. 1003. 1504. 25284. The rms value of a sinusoidal current is _____ times its maximum value. (Grob/452.1.32.23. 1/24. 1/3285. The average value of a symmetrical sinusoidal alternating current over whole cycle is (Grob/452.1. Always positive2. Zero3. +5A4. +2A286. Time period of a 400 Hz. a.c. signal is (Grob/452.1. 20 milliseconds2. 2.5 milliseconds3. 25 milliseconds4. 400 milliseconds287. The greatest value attended during one half of the cycle is called the:(9A,P-343.1. peak value2. average value3. RMS value4. effect value288. No. of alternations in a 50 Hz. a.c signal is (Grob/452.1. 502. 1003. 1504. 200289. The frequency of ac voltage has significant effect on - (BLT)1. transformer 2. the speed of the synchronous motor3. the resistor4. both 1 and 2290. Period of a quantity is defined as(Grob/457)1. number of cycles pr second2. time required to rise from zero to peak and back to zero3. time taken to complete one cycle4. maximum value of voltage or current is either positive or negative direction291. Relation of actual power, reactive power and apparent power should be (Eismin/90)1. App. Power2= real power2+ reactive power22. App. Power = real power + reactive power23

3. App. Power = real power reactive power4. App. Power = real power X reactive power292. Power factor is the ratio of ____ to _____ (Eismin/90)1. actual power, apparent power2. resistance, impedance3. both 1 and 2 are correct4. reactive power, apparent power293. What is meant by "current and voltage are in phase" (9A/343.1. voltage and current are of the same magnitude2. voltage and current have the same frequency3. the voltage leads the current in time4. voltage and current reach their max. and zero value at the same time294. The chief disadvantage of a low power factor is that (BLT)1. more power is consumed by the load2. current required for a given load power is higher3. active power developed by a generator exceeds its rated output capacity4. heat generated is more than the desired amount295. The power factor of a purely resistive circuit is - (Eismin/90)1. zero2. lagging3. leading4. unity296. The max. & min. valued of power factor is (Jeppesen)1. 1 and 02. +1 and 13. +1 and -54.+ 5 and 5297. Many of the larger transport a/c have been equipped with AC electrical system. The reason is (Eismin/210)1. Easier to install 2. Less maintenance required3. More efficient4. All of the above298. In Y-connected 3-phase a.c. supply (Pallette/35)1. line current =1.73 x phase current2. line voltage = phase voltage3. line current = phase current4. phase voltage =1.73 x line voltage299. The r.m.s value of sinusoidal a.c current is equal to its value at an angle of (Pallette/35)1. 90 degree2. 45 degree3. 30 degree4. 90 degree300. The input to an a.c circuit having power factor of 0.8 lagging is 20 kV1. The power drawn by the circuit is(BLT)1. 12 kW 2. 20 kW3. 16 Kw4. 8 kW301. If a capacitor is connected to an a.c. source the current _____ the source voltage by ____(FAA 9A)1. lags 9002. lags 4503. leads 9004. none302. Power is given by ______ in 3 phase alternator(BLT)1.3 VLIL COS2.3 VPIP cos3.3 VLIP COS4.3 VLIP cos303. In AC circuit the product of voltage and current is known as:(BLT)1. apparent power2. real power3. resistance power4. power24

304. It is the symbol of (Eismin-211.1. Y connection2. star connection3. delta connection4. both 1 & 2 are correct305. Power Factor is defined as (Ref. FAA 9A, Pg. 358)1. True power2. true power 3.apparent power 4.reactive powerApparent powerreal power reactive power true power306. Calculate capacitive reactance of 400hz circuit having a capacitance of 50 microfarads: (Dale Crane, P-52.1. 8 ohms2. 0.008 ohmsc 125 ohms4. 12.5 ohmsResistive (R), Capacitive (C) and Inductive (L) Circuits-307. Which statement is true regarding resonance in an a.c. circuit: (Dale Crane, P-52.1. at resonance Z=Xc2. at resonance Z=XL3. at resonance Z=R4. at resonance Z=Lc308. For R-L-C series resonant circuit, the circuit current is (Grob/761/762/763.1. maximum2. equal to V/R 3. in phase with V4. all of the above309. For R-L-C series resonant circuit (9A/761 )1. power factor is unity2. impedance is minimum3. net reactance is zero4. all of the above310. In series R-L-C circuit, voltage drop across capacitor and inductor have a phase difference of _____ degree(9A/761.1. 18002. 9003. 12004. 600311. In series resonant circuit (9A/357)1. XL= XC2. XL> XC3. XL< XC4. XLx XC=1312. The resonant frequency of a series R-L-C circuit depends, (9A/357)1. R2. L3. C4. both L & C313. At resonance, for the series tank circuit, ___ is maximum (9A/357)1. impedance2. current3. both 1 & 2 4. neither 1 nor 2314. A parallel a.c. circuit in resonance will - (9A/357)1. act like a resistor of low value2. have a high impedance3. have current in each section equal to the line current4. have a high voltage developed across each inductive and capacitive section315. At lower frequency than its resonance, in a series RLC circuit- (Grob/761-62-63.1. power factor is leading2. power factor is lagging3. power factor is unity 4. power factor is negativeTransformers-25

316. what remains constant in transformers:1. current2. voltage 3. frequency 4. power5. both 3 and 4317. Power loss due to ohmic heating in a transformer is called: (9A/361.1. magnetic loss2. hysteresis loss3. copper loss4. eddy current loss318. The transmission of power over long distances is done at :- (BLT)1. high voltage2. high current3. high impedance4. high frequency319. Transformers are rated in kVA instead of kW because (BLT/1151.1. Load power factor is often not know2. kVA is fixed whereas kW depends on load-power factor3. Total transformer loss depends on volt-ampere4. It has become customary320. Primary is subjected to 220 V & secondary is stepped down supposed to give an output of 11 V & primarycurrent is 5 A & secondary current is 90 A, the stepped down transformer is 1. 30 %2. 40 % 3. 70 %4. 90 % efficiency321. The voltage transformation ratio is (BLT/1123.1. E 1 / E 22. N 1 / N 23. E 2 / E 14. none322. The no load current of a transformer in terms of full load current is usually (BLT/1129/1130)1. 1 to 3 %2. 3 to 15 %3. 9 to 12 %4. 12 to 20 %323. The iron loss has: (BLT1985-P-597)1. Copper and eddy current loss2. Hysteresis and eddy current loss3. Copper and hysteresis loss4. Copper and flux leakage loss324. The principle of statically induced e.m.f is utilized in (BLT Pg-1029)1. Transformer2. Motor3. Generator4. both 2 & 3325. Voltage across the secondary winding of a transformer is due to :- (9A/585)1. self-induction2. mutual induction3. electrostatic induction4. none of these326. The main purpose of using core in a transformer is to :- (BLT/1116-17)1. decrease iron losses2. prevent eddy current loss3. eliminate magnetic hysteresis4. decrease reluctance of the common magnetic circuit327. When load on secondary of the transformer is increased, the current in primary side will (BLT/1129)1. not be effected2. increase3. decrease4. be the sum of no load current and excessive current drawn due to secondary winding328. Electric power is transferred from one coil to the other coil in a transformer (BLT/1116)1. electrically 2. electro-magnetically3. magnetically4. physically329. A transformer operates (BLT)1. always at unity power factor2. has its own power factor26 3. at a power factor below a particular value4. at power factor depending on the power factor of load330. Which of the following is a correct statement about eddy current (BLT)1. Eddy current improves the efficiency of a motor2. eddy current heat up the metal part3. eddy current used for arc welding4. none331. Which transformer must be constructed to measure the current of the circuit :(BLT/444.1. power transformer 2. auto transformer3. current transformer4. air core transformer332. In a transformer the sinusoidal emf (BLT/1123.1. lags the flux inducing it by 180 degree2. lags the flux inducing it by 90 degree3. leads the flux inducing it by 180 degree4. leads the flux inducing it by 90 degree333. If in a transformer the secondary turns are doubled and at the same time the primary voltage is reduced byhalf, then the secondary voltage will - (BLT/1123.1. be halved2. be four times as high3. not change4. be reduced to a quarter334. Which of the statement given below is correct for the auto transformer(BLT/1187)1. it has to separate windings connected in series externally2. it has only one winding3. it can only step down the voltage4. it is most suitable for power transformation335 By definition a step down transformer is one in which (G rob/587)1. secondary current is more than primary current2. secondary turns are less than primary turns3. secondary winding consists of thinner copper wire4. secondary power is less than primary power336. In a step up transformer, the power output is same as primary input power neglecting the losses, but(Grob/587)1. current is increased in secondary2. current increases & voltage decreases in secondary3. current decreases & voltage increases in secondary4. current & voltage both increase in secondary337. The measure of how well the flux of the primary is coupled into the secondary is called-(Grob/583.1. mutual inductance 2. self-inductance3. coefficient of coupling4. coefficient of excitation338. In practical transformer, the coefficient of coupling is (Grob/583.1. less than 12. more than 13. equal to 1 4. equal to nearly 100339. Permeabilities of copper and aluminium (Jeppesen 3-10)1. higher than iron2. equal to iron3. lower than iron4. none of these340. Lines of magnetic flux always search the (Jeppesen 3-10)1. easy path2. resistive path27 3. vertical path4. horizontal path341. Reluctance is the opposition in the circuit to the flow of (Jeppesen 3-12.1. lines of magnetic flux2. lines of electric flux3. air4. all of the above342. A transformer transfers electric power from one circuit to another without changing its (BLT/117)1. voltage2. current3. frequency4. all of the above343. A transformer in which the core surrounds a considerable portion of the winding is known as (BLT/1117)1. core type transformer2. shell type transformer3. both 1 & 24. none of these344. In a transformer the core is laminated and insulated to reduce the (BLT/1117)1. eddy current loss2. hysteresis loss3. copper loss4. all of the above345. In a transformer if N2> N1i.e. K> 1 then the transformer is called (BLT/1123.1. step down2. step in3. step up4. none of these346. In auto transformer, primary and secondary windings are (BLT/1186)1. isolated by each other2. not isolated from each other3. 1 & 2 both4. none of these347. Ferrite cores commonly used at high frequencies to: (BLT Electronics, P-74.1. increase core losses2. decrease core losses3. decrease inductance 4. increase resistance348. The maximum efficiency of transformer occurs when: (BLT Vol-II, P-1082.1. iron loss is zero2. iron loss is less than copper loss3. iron loss = copper loss4. iron loss > copper loss349. In auto transformer: (BLT Vol-II, P-1090)1. power is transferred inductively and conductively2. there is saving of copper3. both 1 and 24. none350. Current transformer is: (Eismin-P-168)1. Step up2. Step down3. Transformation ratio is unity351. Mark the correct statement: (Eismin-P-108)1. Transformer works on mutual induction principle2. It has eddy current and cu looses while in operation3. Transformer cores are laminated4. All are correct352. Laminated core of transformers provides: (BLT-Vol-II-P-1117)1. Low reluctance path to magnetic field2. High reluctance path to magnetic field3. Low reluctance path to a.c. field4. High reluctance path to a.c. field28 353. A transformer transforms (BLT-VOL-II P-1208)1. Frequency2. Voltage3. Current4. Voltage and current354. Which of the following is not a basic element of a transformer (BLT-VOL-II P-1208)1. Core 2. Primary winding3. Secondary winding4. Mutual flux355. In an ideal transformer (BLT-VOL-II P-1208)1. Winding have no resistance2. Core has no losses3. Core has infinite permeability4. All of the above356. In relation to a transformer, the ratio 20:1 indicates that (BLT-VOL-II P-1208)1. There are 20 turns on primary one turn on secondary2. Secondary voltage is 1/20thof primary voltage3. Primary current is 20 times greater than the secondary current4. For every 20 turns on primary there is one turn on secondary357. The primary and secondary windings of an ordinary 2-winding transformer always have (BLT-VOL-II P-1208)1. Different number of turns2. A common magnetic circuit3. Same size of copper wire4. Separate magnetic circuit358. In a transformer which part is insulated from the other:1. primary and secondary windings2. windings and core3. both 1 and 23. there is no need of insulation in a transformerAC Motors359. If after starting, one connection to 3-phase induction motor is accidentally broken:(FAA 9A)1. motor will always continue to rotate2. motor will continue to rotate if load on motor is less than 1/3rdof full load3. motor will continue to rotate in case of full load only4. motor will never rotate360. Which of the motors is not self starting (BLT/1368)1. two phase induction motor2. series wound dc-motor3. 3 phase induction motor4. Single phase induction motor361. The direction of _________ motor can not be reversed (BLT/1383.1. dc series2. capacitor start induction3. 3 phase induction4. shaded pole induction362. Which of the following is incorrect: (BLT/1248)1. in 3 phase synchronous motor, field is rotating2. in 3 phase induction motor, field is stationary and pulsating3. synchronous motor is inherently not self starting4. synchronous motor can be made self starting363. When load on induction motor is decreased: (BLT)1. speed increases 2. slip decrease3. relative speed decreases4. all of the above364. The starting winding of single phase induction motor is placed in (BLT)1. rotor2. stator3. armature4. field365. A single phase motor is (BLT/1368)1. inherently not self starting2. requires only one winding3. is self starting4. can rotate in one direction only366. In a synchronous motor rotor squirrel cage winding is provided for making the motor: (BLT-1991-P-651.29

1. Noise free2.Self starting3. Cheap 4. Quick start367. Which one is AC operated motor ? [EISMIN, P-183]1. Universal2. induction3. synchronous4. all368. In which motor there is no electrical connection between stator and rotor ? [EISMIN, P-185]1. induction2. synchronous 3 DC 4. both (a) & (b)369. Percentage of difference in speeds of stator and rotor field is called [EISMIN, P-185]1. Slip2. ripple 3. degree4. none370 An electric motor in which stator and rotor poles run with same speed is known as:(Ele3. Notes-P-172.1. Induction motor2. Universal motors3. Synchronous motors4. Differential motor371. If an alternator has 4 poles and 1800 r.p.m frequency is: (Eismin-P-219)1. 60 cps2. 120 cps3. 100 cps4. none of the above372. The magnitude of the e.m.f generated by an alternator depends on:- (Electrical Notes-Page-171.1. Number of its poles2. Rotor speed3. Flux per pole4. All the above373. The alternator is connected to the external circuit by: FAA-9A, P-4111. slip rings & brushes2. commutator3. armature4. fieldAC Generators374. For parallel operation of two alternators, they have (BLT/1456)1. same phase sequence2. same frequencies3. same voltage4. all of the above375. The frequency of the alternator is obtained by: FAA-9A, P-4111. P x N/602. P x N/1803. P/2 x N/604. P x N/360376. The advantage of revolving field type alternator is that:(FAA 9A)1. armature output connected directly to the load without sliding or brush contact in the load circuit2. armature output connected through slip ring3. armature output connected through brush and commutator4. none of the above is correct377. a.c. has largely replace d.C because: (Ref. FAA 9A, Pg. 338)1. If can be transmitted over long distance2. Economical than d.C3. a.c. voltages can be increased or decreased4. All378. Two types of alternator are: (Ref. FAA 9A, Pg. 412.i). Revolving armature alternatorii). Revolving field type alternatoriii). Revolving phases type alternatoriv). Based on brush position1. i) & iv) 2.iii) & iv)3. ii) & iii)4. i) & ii)379. Which of the motors is not self starting (BLT/1368)1. two phase induction motor2. series wound dc-motor3. 3 phase induction motor4. Single phase induction motor380. The direction of _________ motor can not be reversed (BLT/1383.1. dc series2. capacitor start induction3. 3 phase induction4. shaded pole induction381. Which of the following is incorrect: (BLT/1248)30

1. in 3 phase synchronous motor, field is rotating2. in 3 phase induction motor, field is stationary and pulsating3. synchronous motor is inherently not self starting4. synchronous motor can be made self starting382. When load on induction motor is decreased: (BLT)1. speed increases2. slip decrease 3. relative speed decreases4. all of the above383. The starting winding of single phase induction motor is placed in (BLT)1. rotor2. stator3. armature4. field384. A single phase motor is (BLT/1368)1. inherently not self starting2. requires only one winding3. is self starting4. can rotate in one direction only385. In a synchronous motor rotor squirrel cage winding is provided for making the motor: (BLT-1991-P-651.1. Noise free2.Self starting3. Cheap 4. Quick start386 An electric motor in which stator and rotor poles run with same speed is known as:(Ele3. Notes-P-172.1. Induction motor2. Universal motor3. Synchronous motors4. Differential motor387. If an alternator has 4 poles and 1800 r.p.m frequency is: (Eismin-P-219)1. 60 cps2. 120 cps3. 100 cps4. none of the above388. The magnitude of the e.m.f generated by an alternator depends on:- (Electrical Notes-Page-171.1. Number of its poles2. Rotor speed3. Flux per pole4. All the above389. The alternator is connected to the external circuit by: FAA-9A, P-4111. slip rings & brushes2. commutator3. armature4. fieldFILTERS390. A low pass filter circuit contains:(Handbook-P-135)1) A capacitor2) A resistor3) An inductor4) A transistor391. A high pass filter circuit contains:(Handbook-P-136)1) A capacitor2) A resistor3) An inductor4) A transistor392. A low pass filter allows:(Handbook-P-136)1) Low frequencies2) High frequencies393. A high pass filter allows:(Handbook-P-136)1) Low frequencies2) High frequencies394. Band pass filter contains L-C circuit in _____ with output load:(Handbook-P-138)1) series2) parallel395. Band reject filter is formed by connecting one series L-C circuit and one parallel L-C circuit___________ to each other.(Handbook-P-140)1) Parallel2) Series396. Parallel L-C circuit is also called a ______.1) Resonance circuit2) Tank circuit3) Acceptor circuit31

397. The cut of frequency for a high pass filter is that frequency at which the output voltage equals _________of theinput voltage(Handbook-P-138)1. 100%2. 50%3. 70.7%4. 65.3%398. High pass filters are used in passing high frequency to?(Handbook-P-137)1. Tweeter2. Speaker3. Woofer4. None399. The basic function of a filter circuit is?1. To remove ripples2. To give a DC output3. To give a AC output4. NoneElectrical Terminology-400. An electric current is (9A/350)1. random movement of electrons in a conductor.2. movement of free electrons predominately in one direction.3. pressure difference between two poles.4. the power that causes drift of electrons.401. Magneto motive force (MMF) is measured in (Jeppesen 3-12.1. volts2. amperes3. gilberts4. ohms402. Factors affecting the resistance values(B.L Thereja Page-05)1. Cross sectional area2. Length3. Temperature4. All of the above403. Conventional current flows from -1. Positive terminal to negative terminal2. Negative terminal to positive terminal3. Positive to ground4. Both 1 and 3 are correct404. Electron current is the flow of electrons from 1. Positive terminal to negative terminal2. Negative terminal to positive terminal3. Positive to ground4. Both A and C are correct405. Good electric conductor is one having 1. Low conductance2. High resistance3. Produces minimum voltage drop4. Is made of cooper406. The unit of conductance is 1. ohms2. Gilberts3. Siemens4. None407. One volt is equal to -1. Joule / Coulomb2. Coulomb / Joule3. Ohm / Joule4. None of the