## practice set

### SSC JE ELECTRICAL PRACTICE SET - 9

1.
 If an atom loses one or more electrons, it becomes  __________ A Electrically neutral B Electrically positive C Electrically negative D A neutral ion Answer : B Explanation :
2.
 Absorbed moisture contents affect the dielectric strength  __________ A Directly B Indirectly C Does not affect D None of these Answer : B Explanation :
3.
 What will be the capacity of four capacitors of equal capacity  ‘C’ when connected in series A 4C B C/4 C C D 3/4C Answer : B Explanation :
4.
 Two  condensers of capacity 2F and 3F are connected in series , a third condenser of 1F is connected in parallel to them, the resultant capacity in Farad (F) will be A 6/F B 5/11F C 5/6F D 11/5F Answer : D Explanation :
5.
 How will the total capacitance change, when two capacitors are connected in parallel A The total capacitance increases B The total capacitance decreases C The mena value gives the new capacitance D The total capacitance is found by reciprocal equation Answer : A Explanation :
6.
 The electric flux and field intensity inside a conducting sphere is  ___________ A Zero B Maximum C Uniform D Minimum Answer : A Explanation :
7.
 Efficiency is  ____________ A The difference between power input and output B The relation of power input to power output C The relation of power output to the power D The percentage of power output compared with the input Answer : C Explanation :
8.
 The internal voltage drop of a voltage source  ___________ A Is the highest when no load is applied B Does not influence the terminal voltage C Depends upon the internal resistance of the source D Decreases with increases load current Answer : C Explanation :
9.
 If a capacitor is charged by a square wave current source, the voltage across the capacitor is  __________ A A squre wave B Triangular wave C Step function D Zero Answer : B Explanation :
10.
 Kirchhoff is voltage law applied to circuit with  __________ A Linear element only B Non-linear only C Linear, non-linear, active and passive elements D  Linear, non-linear, active, passive time variant as well as time invariant elements Answer : D Explanation :
11.
 Which of the following is an active element of circuit A Resistance B Inductance C Capacitance D Ideal current source Answer : D Explanation :
12.
 Static electricity is produced by  ________ A Chemical reaction B Friction C Induction D Both friction and induction Answer : B Explanation :
13.
 The transient currents are due to  ___________ A Voltage applied to circuit B Resistance of the circuit C Impedance of the circuit D Change in stared energy in inductors and capacitance Answer : D Explanation :
14.
 A coil with large distributed capacitance has  ____________ A Low resistance B Low Q C Low resonant frequency D Hight resonant frequency Answer : D Explanation :
15.
 To a highly inductive circuit a small capacitance is added in series the angle between voltage and current and current will  __________ A Increase B Decrease C Remain nearly the same D Become in – determinant Answer : B Explanation :
16.
 For a prototype low pass filter, the series and shunt elements are respectively A Capacitive and inductive B Inductive and Capacitive C Series combination of Capacitance and inductance D Resistive and inductive Answer : B Explanation :
17.
 For a prototype hight pass filter, the series element is  _________ A Resistive B Inductive C Capacitive D Combination of inductance Capacitance Answer : C Explanation :
18.
 The shunt element of prototype high pass filter is  ____________ A Resistive B Inductive C Capacitive D Combination of inductance and  Capacitance Answer : B Explanation :
19.
 If voltage standing wave radio, (VSWR) of a wave is 2, its reflection coefficient will be  _________ A 0 B 1/2 C 1/3 D 1 Answer : C Explanation :
20.
 A dominant wave is characterized by  ___________ A Lowest attenuation B Highest attenuation C Lowest cut off wavelength D Highest cut off wavelength Answer : C Explanation :
21.
 The standing wave ratio of a 75 Ω transmission line used to feed a 300 Ω resistive load will be  ___________ A 1 B 2 C 3 D 4 Answer : D Explanation :
22.
 Gauge factor of strain gauge is defined as the ratio of per unit change in the  ________ A Conductive to the per unit change in applied force action acting on the element B Resistance to the per unit change in the length of the element C Stress to the per unit change in strain of the element D Current to the per unit change in the length of the element Answer : B Explanation :
23.
 Which one of the following is the best method of measurement of temperature of hot bodies radiating energy in visible spectrum A Thermocouple B Thermopile C Optical pyrometer D Barometer Answer : C Explanation :
24.
 The use of thermocouple meters for AC measurement leads to a meter-scale which is  __________ A Linear B Square law C Logarithimic D Exponential Answer : B Explanation :
25.
 Dummy strain gauge is used in conjunction with the main gain strain gauge to  _________ A Calibrate the system B Compensate temperature effects C Improve sensitivity D Reduce strain on the gauge Answer : B Explanation :
26.
 Match List – 1 (transducer) with  List – 2 (characteristics)  and select the correct answer using codes given below the lists  :      List – 1                              List – 2 P. Thermocouple     1.   Modulated output Q. Thermistor            2. Resistance change with pressure R.  Strain gauge           3.   Negative temperature coefficients  S.   LVDT                           4.   Constant temperature one end A P-3; Q-2; R-4; S-1 B P-4; Q-3; R-2; S-1 C P-2; Q-1; R-4; S-3 D P-1; Q-2; R-3; S-4 Answer : B Explanation :
27.
 In a flux meter, the controlling torque is  __________ A Produced by weights attached to the moving coil B Produced by spring C Not provided at all D Provided by crossed coil mechanism Answer : C Explanation :
28.
 In an energy-meter which coil carries the current proportional to supply voltage  ____________ A Current coil B Pressure coil C  Both pressure and current coil D None of these Answer : B Explanation :
29.
 The function of measurement system  is/are  ____________ A Indicating function B Recording function C Controlling function D Indicating, recording and controlling function Answer : D Explanation :
30.
 Moire fringes are used to measure rotary displacement along with  ___________ A Contact type encoders only B Optical encoders only C Contact type encoders and Optical encoders D None of these Answer : B Explanation :
31.
 In the range of an analog transducer is  0 to 10V, then for a resolution of 5mV. The bits of  ADC will be  ____________ A 8 B 9 C 10 D 11 Answer : D Explanation :
32.
 Which type of earthing is also called as ‘fire earthing’  I. Plate earthing II. Rod earthing III. Strip earthing A Only I B Only II C Only III D I, II & III Answer : B Explanation :
33.
 What is the dimension of the copper strips used for the strip earthing A 25mm × 4mm B 25mm × 3mm C 30mm × 4mm D 30mm × 3mm Answer : A Explanation :
34.
 What type of earthing is used by transmission lines A Plate earthing B Rod earthing C Strip earthing D Both plate and strip earthing Answer : C Explanation :
35.
 What should be the value of earthing resistance for large power stations A 1 Ω B 0.5 Ω C 2 Ω D 5 Ω Answer : B Explanation :
36.
 What is the diameter of the  GI pipe through which the earth wire needs to be taken out A 13 mm diameter B 15 mm diameter C 19 mm diameter D 6 mm diameter Answer : A Explanation :
37.
 Which set of rules are to be verified on completion of wiring on any new installation A Indian Electricity rules, 1950 B Indian Electricity rules, 1956 C Indian Electricity rules, 1960 D None of these Answer : B Explanation :
38.
 Branch circuit must not feed more than  ___________  points A 12 B 5 C 10 D 8 Answer : C Explanation :
39.
 The leakage current must not be more than  _________  of maximum supply current A 1/1000 B 1/100 C 1/5000 D 1/500 Answer : C Explanation :
40.
 Which among these is a type of internal wiring I. Cleat wiring II.Conduit wiring III. CTS wiring A Only I B Only II C Both II & III D I, II & III Answer : D Explanation :
41.
 Which law states that induced  emf  and current always opposes producing them A Len’z law B Fleming’s law C Faraday’s law D Maxwell’s law Answer : A Explanation :
42.
 The main purpose of using core in a transformer is to  _________ A Decrease iron losses B Prevent eddy current loss C Eliminate magnetic hysteresis D Decrease reluctance of the common magnetic circuit Answer : D Explanation :
43.
 During charging, the specific gravity of the electrolyte of a lead acid battery  __________ A Decreases B Remains the same C Increases D None of these Answer : C Explanation :
44.
 The best indication about the state of charge on a lead acid battery is given by  ___________ A Specific gravity of electrolyte B Temperature of electrolyte C Output voltage D None of these Answer : A Explanation :
45.
 In which of the following voltage sources, the movement of conductors in a magnetic field is used to produce voltage A In a thermos couple B In a zinc copper element C  In a DC generator D In a transformer Answer : C Explanation :
46.
 The current transformer that is used to measure a 100 A current by 5 A ammeter is a  ___________ A Step up transformer B Step down transformer C Power transformer D Distribution transformer Answer : A Explanation :
47.
 In dynamometer type of wattmeter, which of the coil is spilt up into two parts A Pressure coil B Current coil C Both Pressure coil  & Current coil D None of these Answer : B Explanation :
48.
 The series magnet of a single phase energy meter consists, coil of  ___________ A Thin wire of few turns B Thik wire of few turns C Thik wire of more turn D Thin wire of more turn Answer : B Explanation :
49.
 The frequency and domain are related through  _________ A Laplace transform only B Fourier integral only C Laplace transform or Fourier integral D Both Laplace transform and Fourier integral Answer : D Explanation :
50.
 The open loop control system is one in which A The output is dependent on control unit B The output is independent no control unit C Only system parameters have effect on the control output D None of these Answer : B Explanation :
51.
 As compared to a cplit phase motor, a capacitor start motor has  _____________ A Higher starting torque B Lower starting torque C Higher running torque D None of these Answer : A Explanation :
52.
 What is called the electro-motive force (emf) of a voltage source A Terminal voltage when load is applied B Internal voltage when no load is applied C Product of internal resistance and load current D Electric pressure provided to the load Answer : B Explanation :
53.
 Which of the following theorems enables a number of voltage (or current) source to be combined directly into a single voltage (or current) source A Compensation theorem B Reciprocity theorem C Superposition theorem D Milliman’s theorem Answer : D Explanation :
54.
 To  neglect a voltage source, the terminals across the source are  ___________ A Open-circuited B Short- circuited C Replaced by some resistance D Replaced by capacitance Answer : B Explanation :
55.
 In a standard multi-meter for measuring  AC  voltage parameter of  ___________  voltage is measured A Peak – to – peak B Peak C Average value D RMS Answer : D Explanation :
56.
 What  happens to current flow in a capacitive circuit when the DC voltage across the capacitor is approximately equal to the source voltage A Current flow is optimized B Little current flows C Current flow is maximum at the source D Current flow is maximum at the capacitor Answer : B Explanation :
57.
 Which of the following devices can be used to test the windings of an induction for continuity A Wattmeter B Voltmeter C Ohmmeter D Wheatstone bridge Answer : D Explanation :
58.
 Which of the following circuit condition does a metal oxide varistor (MOV) protect against A High voltage B High current C High circuit noise D High cross-talk Answer : A Explanation :
59.
 How should a fuse be installed in a circuit to insure proper operation A Parallel to the load B Series with the load C In any way possible D At the ground point Answer : B Explanation :
60.
 Fermi energy level for n-type extrinsic semiconductors lies  __________ A At middle of the band gap B Close to valenec band C None of these D Answer : B Explanation :
61.
 Centrifugal Methods of reconditioning transformer oil is effective for removel of  ___________ A Water B Dissolved gases C Solid impurities D All options are correct Answer : A Explanation :
62.
 A generating voltmeter uses  _____________ A A constant speed motor B A variable speed motor C A variable speed motor with a capacitor D None of these Answer : A Explanation :
63.
 A servo system must have  ____________ A Feedback system B Power amplifier to ampify error C Capacity to control position or its derivative. D All options are correct Answer : D Explanation :
64.
 The major disadvantage of a feedback system many be  ___________ A Inaccuracy B Inefficiency C Unreliability D Insatability Answer : D Explanation :
65.
 What is the effect produced by the electric current in an electric motor A Magnetic, effect only B Magnetic as well as heating effect C Heating effect only D Heating as well as chemical effect Answer : B Explanation :
66.
 The rotating part of a  DC  motors is known as  __________ A Pole B Stator C Armature D Carbon brush Answer : C Explanation :
67.
 Why is the air gap between the yoke and armature of an electric motor kept smaller A To achieve a stronger magnetic field B To avoid overheating of the machine C To make station easier D None of these Answer : A Explanation :
68.
 The function of the commutator in a DC machine is  ____________ A To change alternating current into direct current B To improve commutation C For easy speed control D For change alternating voltage into direct voltage Answer : A Explanation :
69.
 DC shunt generator has  ___________ A Slightly drooping characteristic curve B Appreciably rising characteristics C Constant voltage characteristics D Appreciably falling characteristics Answer : A Explanation :
70.
 Which of the following generators is used for charging batteries A Compound generator B Shunt generator C Series generator D Tacho generator Answer : B Explanation :
71.
 The speed of a DC motor is  _____________ A Directly proportional to back emf and inversely proportional to flux B Inversely proportional to back emf and directly proportional to flux C Directly proportional to emf as well as to flux D Inversely proportional to emf as well as to flux Answer : A Explanation :
72.
 The emf of a DC generator depends on  ___________ A Commutation B Speed C Frequency D Brush contact drop Answer : B Explanation :
73.
 In DC motor, where does iron loss occur A The yoke B The armature C The field D None of these Answer : A Explanation :
74.
 The dummy coil in DC machines is used to  _____________ A Eliminate reactance voltage B Eliminate armature reaction C Bring about mechanical balance of armature D Eliminate harmonics developed in the machine Answer : C Explanation :
75.
 A simple method of increasing the voltage of a DC generator is __________ A To decrease the air gap flux density B To increase the speed of rotation C To decrease the speed of rotation D To increase the length of the armature Answer : B Explanation :
76.
 The speed of a  DC  shunt motor is required to be more than  F.L (Full Load) speed. This is possible by  ___________ A Increasing the armature current B Decreasing the armature current C Increasing the excitation current D Redusing the field current Answer : D Explanation :
77.
 An emf is induced in the windings of an armature of a DC generator when the armature rotates in  ____________ A Alternating magnetic flux B Magnetic field C Electrostatic field D Electromagnetic flux Answer : B Explanation :
78.
 The function of a commutator in a DC generator is  ____________ A To collect current from conductors B To change DC into AC C To conduct the current to the brushes D To change ac into DC Answer : D Explanation :
79.
 The current flowing in the conductors of a DC motor is  __________ A AC B DC C AC as well as DC D Transients Answer : A Explanation :
80.
 As the load is increased, the speed of a dc shunt motor will  _________ A Remain constant B Increase proportionately C Increase slightly D Reduce slightly Answer : D Explanation :
81.
 If the current in the armature of DC series motor is reduced to 5% the torque of the motor will become  _____________ A 50 % of the previous value B 25 % of the previous value C 150 % of the previous value D 125 % of the previous value Answer : B Explanation :
82.
 The direction of rotation of a DC shunt motor is reversed by  __________ A Reversing armature connection B Interchanging the armature and field connection C Adding resistance to the field circuit D Reversing supply connections Answer : A Explanation :
83.
 Which of the following is a correct statement about a series motor A Its field winding consists of thicker wire and less turns B It can run easily without load C It has as almost constant speed D It has poor torque Answer : A Explanation :
84.
 The motor that is used for intermittent, high torque load is  __________ A DC shunt motor B DC series motor C Differential compound motor D Cumulative compound motor Answer : D Explanation :
85.
 For which of the following DC motor, the typical field of application mentioned A Shunt motor  :  Electric trains B Series motor  :  Machine tools C Series motor  :  Bell drive D Compound motor  :  Fly wheel drive Answer : D Explanation :
86.
 The generator of power station produces an electric pressure by  ____________ A Conversion of heat B Magnetic induction C Conversion of light D Mechanical pressure Answer : D Explanation :
87.
 A DC generator can be termed as  ____________ A Rotating amplifier B Prime mover C Power pumpNone of these D None of these Answer : A Explanation :
88.
 The parts of the armature electric circuit which take active part in  emf  generator are  ___________ A The coil sides inside the slots B The overhangs C Both the coil sides thwe slots and the overhangs D The commutator segments Answer : A Explanation :
89.
 The wave form of the armature  mmf  in DC machine is  ____________ A Square B Rectangular C Triangular D Sinusoidal Answer : C Explanation :