Q.41  The Power- factor at resonance in R-L-C circuit is        (A) Zero.         (B) Unity.   (C) 0.5 lagging. (D) 0.5 leading.  

  Ans: B  

Q.42  In an 8 – pole wave connected motor armature, the number of parallel paths are         (A) 8 (B) 4    (C) 2 (D) 1                                            

  Ans: C  

Q.43  Transformer core is laminated to      (A) Reduce the copper losses.        (B) Reduce the core losses.    (C) Reduce the eddy current losses. (D) None of these.  

  Ans: C Q.44  The relation between frequency, speed and number of poles is given by      (A) p. xfN120 s = (B) p. Nx 120f s =    (C) f . xpN120 s =                        (D) 120. f x pN s =  

  Ans: A  

Q.45  Star – delta starter of an induction motor     (A) Inserts resistance in rotor circuit.    (B) Inserts resistance in stator circuit.    (C) Applies reduced voltage to rotor.                           (D) Applies reduced voltage to stator.  

Ans: D  

Q.46  Stator core of an induction motor is made of    (A) Laminated cast iron.                    (B) Mild steel.                                                        (C) Silicon steel stampings. (D) Soft wood.  

  Ans: C  

Q.47  Watt hour is the unit of       (A) Electric power. (B) Electric capacity.                                                    (C) Electric energy. (D) Electric charge.  

  Ans: C  

Q.48   A battery is a source of      (A) DC voltage. (B) 1 φ AC voltage.     (C) 3 φ AC voltage. (D) AC or DC voltage. 

  Ans: A  

Q.49 Which DC motors has approximately constant speed?    (A)  Series motor. (B)  Shunt motor    (C)  Cumulatively compound motor (D)  All of the above.  

 Ans: B  

Q.50  Which of the following bulbs will have the least resistance?       (A)  220V, 60W  (B)  220 V, 100 W       (C)  115 V, 60 W                               (D)  115V, 100 W  

 Ans: D  

Q.51  Resistance of a wire is  r ohms. The wire is stretched to double its length, then its resistance in ohms is    (A)  r/2 (B)  4r    (C)  2r (D)  r/4  

 Ans: B  

Q.52  An electric machine will have high efficiency when        (A)  input/output ratio is low  (B)  reactive power is more      (C)  kWh consumption is low  (D)  losses are low  

 Ans: D  

Q.53  Which type of loss is not common to transformers and rotating machines?    (A)  Eddy current loss        (B)  Copper loss      (C)  Hysteresis loss                  (D)  Windage loss  

 Ans: D  

Q.54  The difference between the synchronous speed and the actual speed of an induction motor is known as       (A)  Regulation (B)  back lash      (C)  slip (D)  lag  

 Ans: C  

Q.55  In two wattmeter method of power measurement, if one of the wattmeter shows zero reading, then it can be concluded that       (A)  Power factor is unity (B)  Power factor is zero             (C)  Power factor is 0.5 lagging  (D)  Power factor is 0.5 leading  

 Ans: C 

Q.56  Which of the following will remain the same in all parts of a series circuit?    (A)  Voltage                                     (B)  Current                                                         (C)  Power (D)  Resistance  

 Ans: B    

Q.57  Which single phase motor would you select for a tape recorder?        (A)  Reluctance motor (B)  Hysteresis motor                                                     (C)  Synchronous motor (D)  Universal motor  

 Ans: B  

Q.58  Under the condition of resonance, RLC series circuit behaves as a,  (A) Purely resistive circuit. (B)  Purely inductive circuit. (C) Capacitive circuit. (D) Reactive circuit.  

Ans:A    Q.59    During charging, the electrolyte of a lead acid cell becomes         (A) Stronger. (B) Weaker.   (C) Water. (D) Diluted.     

 Ans:D  

Q.60   As compared to shunt and compound motors, series motor have the highest torque because of its comparatively __________ at the start.  (A) Lower armature resistance. (B)  Stronger series field. (C)  Fewer series turns. (D)  Larger armature current.  

 Ans:D  

Q.61   The input of an ac circuit having p.f. of 0.8 lagging is 20 kVA.  The power drawn by the circuit is __________ kW.    (A) 12.         (B)  20. (C)  16.     (D)  8.  

  Ans: C  

Q.62  The voltage ratio of the transformer is given as (A) SP EE (B)  SP TT (C) PS TT (D) PS ET  

  Ans:A  

Q.63  The relationship between the frequency of ac wave and the time period is given by 

(A) f = T (B)  2 1Tf = 

(C) 1T f = (D) 2 Tf =  

  Ans: C   

Q.64 Which of the following power plant has the maximum efficiency? (A)  Thermal (B) Hydroelectric (C)  Nuclear (D) Diesel  

 Ans:C  

Q.65  Three capacitors of value 8F µ , 16F µ and 32 F µ are connected in series, the total capacitance will be  (A) F 7  32 µ . (B) 7.32 F µ .     (C) 56 F µ . (D) 32 F µ .  

  Ans: A  

Q.66  The following components are all active components (A) a resistor and an inductor.  (B) a diode, a BJT and an FET. (C) a capacitor, and an inductor.  (D) an Opamp, a BJT and thermionic triode.  

  Ans: B  

Q.67  In forward mode NPN BJT, if we increase the voltage CCV , the collector current increases (A) due to ohm’s law, higher CCV causes higher current.  (B) due to base width decrease less carrier recombine in the base region. (C) as the gradient of the minority carriers in the base region becomes steeper. (D) due to both the reasons (B) and (C).  

  Ans: D  Q.68  The barrier voltage ( ) ro or V V  in a junction diode is the effect of  (A) the p-side and n-side of the junction forming a battery.  (B) the emf required to move the holes fast enough to have the mobility equal to that of the electrons. (C) the recombination of charge carriers across the junction leaving behind the opposite charged ions.  (D) the voltage needed to make the semiconductor material behave as a conductor.  

  Ans:C   

Q.69  An emitter follower has high input impedance because  (A) large emitter resistance is used.  (B) large biasing resistance is used. (C) there is negative feedback in the base emitter circuit.  (D) the emitter-base junction is highly reverse biased.      Ans: C  

Q.70  In a differential amplifier an ideal CMRR is  (A) infinity. (B) zero. (C) –1. (D) +1.      Ans: A  

Q.71  FET is advantageous in comparison with BJT because of   (A)  high input impedance. (B)  high gain-bandwidth product. (C) its current controlled behaviour. (D)  high noise immunity.  

  Ans: A  

Q.72  The emission of electrons in a vacuum diode is achieved by  (A) electrostatic field. (B)  magnetic field. (C)  heating. (D)  electron bombardment.  

  Ans: C  

Q.73  The colour code of a resistor of nominal value ± ΩK2.7 10% is        (A)  Red, violet, red and silver. (B)  Red, violet, yellow and gold. (C)   Red, violet, orange and silver. (D)  Red, violet, red and gold.  

  Ans: A   Q.74  Capacitor that can have the highest capacitance value is  (A) Mica (B)  Paper  (C)  Electrolytic (D)  Ceramic          Ans: C  

Q.75  The equivalent current-source representation for a voltage-source with open circuit voltage 12 V and internal resistance 3 ohms is     (A)  a current-source of strength 4A in shunt with a resistance of Ω 6 .  (B)  a current –source of strength 4A in series with a resistance of Ω 3 . (C)  a current-source of strength 4A in shunt with a resistance of 3 ohms. (D) a current-source of strength 4A in shunt with a resistance of 36 ohms.   

  Ans: C  

Q.76  An intrinsic semiconductor at absolute zero temperature 

        (A)  has a large number of holes.  (B) behaves like an insulator.         (C)  behaves like a metallic conductor.         (D)  has few holes and same number of electrons.   

   Ans: A  

Q.77  The current flow through a Ge PN junction diode with a forward bias of 0.22 Volt and a 

reverse saturation current of 1 mA at 25C o

 is around   (A) 6.3 A         (B)  5.22 A (C)  4 mA         (D)  5.1 mA  

  Ans: B  

Q.78  For the operation of a depletion-type N-MOSFET, the gate voltage has to be  (A) low positive (B)  high positive (C)  high negative (D)  zero  

  Ans: D  

Q.79  The typical operating voltage for LED’s ranges from (A) 0.2 V to 0.6 V. (B)  6 V to 10 V. (C)  1.5 V to 2.5 V. (D)  9 V to 10 V.  

  Ans: C  

Q.80  Capacitors for integrated circuits (A) cannot be made using diffusion techniques.  (B) can be made with very high values of capacitance. (C) are always discrete components connected externally.  (D) can be made using silicon dioxide as the dielectric.  

  Ans: D  

Q.81  The magnitude of variation in the output voltage for a 10 V regulated dc power supply of 0.002% regulation will be  (A)  0.2 mV. (B) 0.002 mV. (C) 0.02 mV. (D) 0.2 V µ .  

  Ans: A Q.82  For the circuit shown in Fig.1, the output voltage is given by        

 (A)  ( ) 21 1 F o vv R R v =− .  (B)  ( )12 2 1 F o vv v R R v −− = . (C)  ( )12 2 1 F o vv v R R v −+ = .  (D) ( )( ) 1F 21 o RR vv v + −= .  

  Ans: C  

Q.83  Which one of the following statements is not true?        (A)  Capacitance is a measure of a capacitor’s capability to store charge. (B)  A  capacitor offers high impedance to ac but very low impedance to dc. (C)  A capacitor is also used as bypass capacitor. (D)   Capacitors are used to couple alternating voltages from one circuit to another and at the same time to block dc voltage from reaching the next circuit.      Ans: B  

Q.84  A voltage source having an open-circuit voltage of 100 V and internal resistance of 50Ω is equivalent to a current source (A) 2A in parallel with 50Ω. (B) 2A with 50Ω in series. (C) 0.5A in parallel with 50Ω. (D) 2A in parallel with 100Ω.           Ans: A  

Q.85  In a Zener diode large reverse current is due to      (A) collision. (B) presence of impurities. (C) rupture of bonds   (D) lower resistance in reverse biased                                                                    region.   

  Ans: D  

Q.86  Ripple factor of a full-wave rectifier without filter will be  (A)  0.2. (B) 0.48. (C)  0.24. (D)  1.21.   

  Ans: B  

Q.87  JFET has main drawback of     (A)  having low input impedance.          (B) having high output impedance. (C) being noisy.           

(D) Having small gain-bandwidth product.  

  Ans: D  

Q.88  A UJT has   (A)  stable negative resistance characteristics.  (B) low firing current. (C) use as a waveform generator.  (D) all of these characteristics.  

  Ans: D  

Q.89  For thermionic emission  (A)  a material with high work function is preferable.  (B) a material with low work function is preferable. (C) the work function of the material has no importance.  (D) None of these is true.  

  Ans: B  

Q.90  Ideal operational amplifier has input impedance of  (A) Ω M1 . (B)  infinity. (C)  zero. (D)  Ω 1 .  

  Ans: B  

Q.91  The CE configuration amplifier circuits are preferred over CB configuration amplifier circuits because they have (A) lower amplification factor.  (B)  Larger amplification factor. (C) high input resistance and low output resistance.  (D) none of these.  

  Ans: B  

Q.92  The most commonly used type of electron emission in electron tubes is  (A) Photo-electron emission. (B)  Thermionic emission. (C) Field emission. (D)  Secondary emission.  

  Ans: A   

Q.93  The colour band sequence of a resistor is grey, Blue, gold, and gold.  The range in which its value must lie so as to satisfy the tolerance specified is between        (A)  Ω 7.5 and Ω 8.5 (B)  Ω K3.12 and Ω K5.22 (C) Ω K.310 and Ω K.3112 (D)  Ω 8.17 and Ω 9.03   Ans: D