## practice set

### SSC JE ELECTRICAL PRACTICE SET - 4

1.
 The colour band at the extreme left of the colour coded resistor represents. A First significant digit B Decimal multiplier C Wattage rating D Voltage rating Answer : A Explanation : Colour coding of resistor shows the value of resistor.                               First band – for the first digit                               Second band – for the second digit                               Third band – gives the no. of zeros that follow the first two digits.                               Fourth band – gives the manufacturing tolerance.
2.
 Which property of an electrical conductor opposes the flow of current through it A Conductance B Resistance C Reluctance D Permeance Answer : B Explanation :
3.
 Ohm is the SI unit of  _________. A Capacitance B Inductance C Resistance D Conductance Answer : C Explanation :
4.
 What will be the resistance (in ohms) of a resistor, when the dissipated power and the current flowing through the resistor is  12 W  and 2 A respectively A 6 B 24 C 2 D 3 Answer : D Explanation :
5.
 What will be the resistance (in ohms) of a cylindrical wire, if the length, diameter and the resistivity of the wire is  4 m, 0.2 m and 0.4 Ohms-m respectively A 49 B 56 C 54 D 51 Answer : D Explanation :
6.
 Which of the following material has the highest resistivity A Insula tors B Conductors C Semiconductors D Super conductor Answer : A Explanation :
7.
 Determine the power (in W) of a lamp of  220 V, when the resistance of the lamp is  100 Ohms A 448 B 486 C 484 D 488 Answer : C Explanation :
8.
 What will be the voltage (inV) of a battery connected to a parallel plate capacitor with air as dielectric, having plate area of  6 sq.  cm  and separation between the plates is  2  mm,  which stores a charge of  8.0 pC   on the plates A 3 B 9 C 6 D 5 Answer : A Explanation :
9.
 What will be the value of current  ‘I’  (in A)  for the given circuit  diagram  Figure A 8 B 4 C 2 D 6 Answer : B Explanation :
10.
 Find the power delivered in (in W)  by the current source in the circuit diagram given below Figure A 300 B 400 C 500 D 600 Answer : B Explanation :
11.
 The algebraic sum of all the voltage around any closed path is  _______ A Negative B Zero C One D Infinite Answer : B Explanation :
12.
 Which one of the following law is based on the principle of conservation of electric charge A Kirchhoff’s Current Law B Kirchhoff’s Voltage Law C Ohm’s Law D Coulomb’s Law Answer : A Explanation :
13.
 The source resistance of an ideal voltage source should be  _________ A Infinite B One C Zero D Greater than one Answer : C Explanation :
14.
 What will be the voltage (in V)  across resistor R2 in the circuit given below  Figure A 14.35 B 13.33 C 15.45 D 12.33 Answer : B Explanation :
15.
 What will be the value of current (in MA)  for the given electrical circuit  Figure A 0.11 B 110 C 0.101 D 101 Answer : D Explanation :
16.
 Which one of the following statement is  NOT  true about the magnetic lines of force A They attract each other while travelling in the same direction. B They behave like a stretched elastic string C They do not cross each other D They can pass through all media Answer : C Explanation :
17.
 The relative permeability of paramagnetic material is  ________ . A Slightly greater than zero B Equal to zero C Equal to one D Greater than one Answer : D Explanation :
18.
 The  SI  unit of magnetic flux density is  _________ A Henry B Tesla C Coulomb D Weber Answer : B Explanation :
19.
 Which one of the following is the formula of Intensity of magnetization A $\frac{\phi}{F_{m}}$ B $\frac{NI}{I}$ C $\frac{m}{A}$ D $\frac{B}{H}$ Answer : B Explanation :
20.
 What will be the coefficient of self-induction (in H)  of the coil, if the current changes from  +4 A to – 4 A in 0.10-seconds and the induced  EMF is  16 V A 1.2 B 2 C 0.2 D 0.8 Answer : C Explanation :
21.
 Calculate the intensity of magnetization (in A-m-1) in a material, if the magnetic field strength of the material is  1800 Amp-m-1 and the magnetic susceptibility is 0.4 × 10-5 A 0.0058 B 0.0072 C 0.0061 D 0.0035 Answer : B Explanation :
22.
 What will be the produced mmf  (in Amp-turns) in a magnetic circuit, if it has 100 number of turns and carrying a current of  0.2 A A 20 B 40 C 500 D 200 Answer : A Explanation :
23.
 What will be the flux density (in T) of a material in free space, if the field strength of the material is  2 × 105  Am- 1 and the magnetic susceptibility of the material is  0.44 × 10- 3 A 0.25 B 0.5 C 0.75 D 1 Answer : A Explanation :
24.
 Determine the value of time  (in Se)  when an average  EMF  of 100 V  is induced in a coil of area  200 cm2  with  100 turns, when  it is completely removed form a magnetic field of  30 T acting at right angles to the coil A 0.4 B 0.2 C 0.6 D 0.9 Answer : C Explanation :
25.
 What is the average value of a  DC  voltage having a peak value of  25 V A 0 B 17.73 C 22.5 D 25 Answer : D Explanation :
26.
 The wave from given in the figure below is an example of  ________  waveform Figure A Sinusoidal B Rectangular C Square D Sawtooth Answer : D Explanation :
27.
 The inductive reactance of a circuit is  60 ohms when it is supplied with a  50 Hz supply. What will be the value of inductive reactance  (in ohms)  of the circuit, if it is supplied with  60 Hz supply A 72 B 86 C 94 D 105 Answer : A Explanation :
28.
 Calculate the impedance  (in ohms)  of the series  RLC  circuit given in the figure below  Figure A 130 B 120 C 13 D 12 Answer : A Explanation :
29.
 Calculate the value of the quality factor of a series  RLC  circuit having resistance, inductance and capacitance of 30 ohms, 27 mH and 0.03 mF respectively A 0.86 B 1 C 2.6 D 3 Answer : B Explanation :
30.
 What is the bandwidth (in kHz)  of a series  RLC  circuit having resistance, inductance and capacitance of 80 ohms, 2 mH and 0.01 mF respectively A 10 B 20 C 40 D 80 Answer : C Explanation :
31.
 Calculate the time taken (in seconds) by the capacitor to get fully charged in a series RC  circuit having resistance and capacitance of 40 kilo-Ohms and 0.01 mF respectively A 1 B 2 C 3 D 4 Answer : B Explanation :
32.
 What is the value of line voltage (in kV)  of a 3-phase star connected system having a phase voltage of  3.3 kV A 2.1 B 3.3 C 5.7 D 6.8 Answer : C Explanation :
33.
 A 3-phase star connected system is supplied by a line voltage of  440 V. The value of phase current is  50 A. What is the power (in kW)  consumed by the system, if the current lags the voltage by  45 degrees A 8.95 B 24 C 26.94 D 47 Answer : C Explanation :
34.
 What is the magnitude of reactive power (in kVAR)  of a balanced 3-phase delta connected system having a line voltage of  400 V  and a line current of 50 A and the phase difference between the voltage and current is  53.13 degrees A 0.2771 B 2.771 C 27.71 D 277.1 Answer : C Explanation :
35.
 Which of the following is the dimension of inductance A $\frac{ML^{2}}{Q^{2}}$ B $\frac{Q^{2}T^{2}}{ML}$ C $\frac{ML^{2}}{QT^{2}}$ D $\frac{ML^{2}}{QT^{3}}$ Answer : A Explanation :
36.
 Which of the following is a type of recording instrument A Ammeter B Megger C Voltmeter D X-Y plotter Answer : D Explanation :
37.
 In  ‘two-wattmeter method’  of power calculation of a 3-phase balanced star connected system, what is the power factor of the system if both the watt-meters show a positive reading A 0 B Greater than 0 but less than 0.5 C 0.5 D Greater than 0.5 but less than 1 Answer : D Explanation :
38.
 A resistance of  75 Ohms is connected in shunt of a galvanometer, having an internal resistance of  25 ohms, to convert it into an  ammeter. What is the value of current (in A) flowing through the galvanometer, if the total current in the circuit is  5 A A 2 B 2.5 C 3.65 D 3.75 Answer : C Explanation :
39.
 Which of the following is  TRUE  about Analog multi-meter A It is a type of absolute instrument B It is a type of indicating instrument C It is a type recording instrument D It is a type of integrating instrument Answer : B Explanation :
40.
 The circuit given below is a circuit of  _________  bridge. Figure A Anderson’s B Kelvin’s Double C Maxwell’s  inductance D Wheatstone Answer : C Explanation :
41.
 Which of the following materials when used as the viewing surface of a  CRO  gives a reddish glow A Zinc sulphide with copper as impurity B Zinc sulphide with silver as impurity C Yttrium oxide D Pure zinc sulphide Answer : C Explanation :
42.
 Which of the following is  TRUE  about current transformers A It decreases the range of AC ammeter B It decreases the range of DC ammeter. C It increases the range of AC ammeter D It increases the range of DC ammeter Answer : C Explanation :
43.
 Which of the follow produces breaking torque in induction type energy meter A Air dampers B Eddy current C Spring D Gravity Answer : B Explanation :
44.
 Which of the following can be used to measure frequency A Anderson’s Bridge B De-Sauty’s Bridge C Owen’s Bridge D Wien’s Bridge Answer : D Explanation :
45.
 The loss associated with the mechanical friction of a machine are called  ________ A Eddy current loss B Mechanical loss C Stray load loss D Hysteresis loss Answer : B Explanation :
46.
 For a 3-phase load balanced condition, each phase has the same value of  ________ A Impedance B Resistance C Power factor D All options are correct Answer : D Explanation :
47.
 A short circuit test on a transformer gives  _________ A Copper loss at full load B Copper loss at any load C Copper loss at half load D Copper loss at over load Answer : B Explanation :
48.
 Armature reaction effect causes flux to reduce with  ________ A Decreasing torque B Increasing torque C Increase current D Both Increasing torque  &  Increase current Answer : C Explanation :
49.
 The armature of a  DC  machine is made of  ________ A Mild steel B Silicon steel C Stainless steel D Cast steel Answer : B Explanation :
50.
 DC  generators are designed to develop armature voltages not exceeding  650 V  because of the limitations of  ________ A Field winding B Armature winding C Commutator D Starters Answer : C Explanation :
51.
 A step up transformer increases  ________ A Power B Voltage C Frequency D Current Answer : B Explanation :
52.
 It is economical to transmit electricity at a  ________ A Very high voltage B Very low voltage C Very high current D Non of these Answer : A Explanation :
53.
 Rotating magnetic fields are also used in 3-phase induction motors rotor developing  ________ A Eddy current B Voltage lag C Load current D Phase current Answer : A Explanation :
54.
 One of the speed control methods of a 3-phase induction motors is  ________ A V/F  control B Stator current control C Core loss control D Eddy current control Answer : A Explanation :
55.
 A centrifugal switch is provided for disconnecting the auxiliary winding in a  _________ A Capacitor-start motor B Capacitor run motor C Reluctance motor D Hysteresis motor Answer : A Explanation :
56.
 In a split phase motor, the running winding should have  ________ A High resistance and Low inductance B Low resistance and High inductance C High resistance as well as High inductance D Low resistance as well as Low inductance Answer : B Explanation :
57.
 A reluctance motor A Is self-starting B Is constant speed motor C Needs no DC excitation D All options are correct Answer : D Explanation :
58.
 The speed control of a universal motor used for sewing machines is done by  ________ A Friction B Varying the resistance C Tapping the field D Centrifugal mechanism Answer : B Explanation :
59.
 The power factor of a single-phase induction motor is usually  ________ A Lagging B Always leading C Unity D Unity to  0.8 leading Answer : A Explanation :
60.
 Hysteresis motors are suitable for  ________ A Fans B Blowers C Sound equipment D Mixer grinders Answer : C Explanation :
61.
 A relay used on short transmission lines is  ________ A Reactance relay B Mho’s relay C Impedance relay D None of these Answer : A Explanation :
62.
 The highest voltage transmission line starting from generating point is called  ________ A Secondary transmission B Secondary distribution C Primary transmission D Primary distribution Answer : C Explanation :
63.
 A  30 km  transmission line carrying power at  33 kV is known as  ________ A Short transmission line B Long transmission line C High power line D Ultra high voltage line Answer : A Explanation :
64.
 The insulating material for cables should be  ________ A Non-hygroscopic B Non-inflammable C Acid proof D All options are correct Answer : D Explanation :
65.
 Name the equipment which runs an alternator. A Motor B Generator C Prime mover D Fan Answer : C Explanation :
66.
 Electric strength in a cable is more on  ________ A Layer on the conductor B Outside conductor C Outer side of armouring D None of these Answer : A Explanation :
67.
 In places where acids and Alkalies are present, the type of wiring used is  ________ A PVC B TRS C VIR D Weather proof Answer : B Explanation :
68.
 Replacement of wiring is not easy in which type of wiring  ________ A Conduit system B Lead sheathed C Concealed wiring D Cleat system Answer : C Explanation :
69.
 ACSR conductor means A All conductor steel reinforced B Aluminium conductor steel reinforced C Aluminium conduit steel rein forced D All conduit steel reinforced Answer : B Explanation :
70.
 The value of supply voltage for  500 W,  5 ohm  load is  ______ A 100 V B 500 V C 50 V D 10 V Answer : C Explanation :
71.
 The most important factor with respect to lighting quality is A Colour B Glare C Illumination D Uniform lighting Answer : B Explanation :
72.
 In ACSR conductors, the insulation between aluminium and steel conductors is  ________ A Varnish B Bitumen C Ceramic D No insulation is required Answer : D Explanation :
73.
 Which one of the given fuse is bigger  ________ A DC B AC C DC or AC D AC and DC are same Answer : A Explanation :
74.
 What is the function of choke in a fluorescent lamp A Starting purpose B Produce high voltage at starting C Improve power factor D Minimize the power consumption Answer : B Explanation :
75.
 In an electric heater, the metal case is connected to  ________ A Phase wire B Earth wire C Neutral wire D None of these Answer : B Explanation :
76.
 Which of the following is not an indoor lighting A Residence light B Office light C Industry light D Flood light Answer : B Explanation :
77.
 Carbon arc lamps are commonly used in  ________ A Domestic lighting B Street lighting C Cinema projectors D Photography Answer : C Explanation :
78.
 Lumen/watt is the unit of  _______ A Light flux B Luminous intensity C Brightness D Luminous efficiency Answer : D Explanation :
79.
 Arc can be produced by A AC  current only B DC current only C Either  AC or DC  current D All options are correct Answer : C Explanation :
80.
 A rectifier for welding has voltage/current  characteristics as  _________ A Drooping B Rising C Static D Variable Answer : A Explanation :
81.
 The insulating material suitable for low temperature applications is  ________ A Cork B Diatomaceous earth C Asbestos paper D 75 percent magnesia Answer : A Explanation :
82.
 The method suitable for heating of conducting medium is  _________ A Induction heating B Indirect arc heating C Eddy current heating D Radiant heating Answer : A Explanation :
83.
 The number of valence electron in boron is  ________ A 1 B 2 C 3 D 5 Answer : C Explanation :
84.
 The potential barrier acts as a barrier against the flow of  ________ A Electrons only B Holes only C Electrons and holes D None of these Answer : C Explanation :
85.
 The plate current in a triode can be controlled by controlling  ________ A Plate voltage B Grid voltage C Plate voltage  and  grid voltage D Grid current Answer : B Explanation :
86.
 A transistor consists of  ________ A One p-n junction B Two p-n junction C Three p-n junction D Four p-n junction Answer : B Explanation :
87.
 The  CE  amplifier is most commonly used because of   _________ A Less power gain B Less output voltage C More power gain D Low cost Answer : B Explanation :
88.
 Synchronous motor shaft is made of   ________ A Alnico B Chrome steel C Mild steel D Stainless steel Answer : C Explanation :
89.
 A Synchronous motor has better power factor than an induction motor. This is due to  _________ A Stator supply is not required to produce magnetic field B Synchronous motor has no slip C Mechanical load on the rotor remains constant D Synchronous motor has large airgap Answer : A Explanation :
90.
 When the field circuit of an unloaded salient pole Synchronous motor gets suddenly open circuited, then  __________ A The motor stops B It runs at a slower speed C It continues to run at the same speed D It runs at a very high speed Answer : C Explanation :
91.
 The resultant armature voltage of a Synchronous motor is equal is equal to the  __________ A Vector sum of Eb and V B Vector difference of Eb and V C Arithmetic sum of Eb and V D Arithmetic difference of Eb and V Answer : B Explanation :