One Stop GATE Forum: 1999- year EE GATE Paper

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1.  This question consists of  20 sub-questions. Each sub-question 
carries ONE mark. The answers to these sub-questions MUST be written only in 
the appropriate boxes corresponding to the questions in the first page of the 
answer book.  

1.1  When  the  plate  area  of  a  parallel  plate  capacitor  is  increased  keeping  the 
capacitor voltage constant, the force between the plates   
  (a)  increase  (b)  decreases  (c)  remains constant 
 (d)  may increase or decrease depending on the metal making up the plates 

1.2  Two parallel wires separated by a distance d are carrying a current I in the same 
direction.  The  magnetic  field  along  a  line  running  parallel  to  these  wires  and 
midway between them 
  (a)  depends upon I      (b)  is zero 
 (c)  depends upon d 
 (d)  depends upon the permeability of medium between the wires 

1.3  An electromagnetic field is radiated from 
 (a)  a stationary point charge  (b)  a capacitor with a DC voltage 
 (c)  a conductor carrying a DC current  (d)  an oscillating dipole 

1.4  As  the  temperature  is  increased,  the  voltage  across  a  diode  carrying  a  diode 
carrying a constant current 
  (a)  increases      (b)  decreases 
 (c)  remains constant 
 (d)  may increase or decrease depending upon the doping levels in the junction  10 samples  per 

1.5  A  single  channel  digital  storage  oscilloscope  uses  a  10  bit,  7second Analog-to-Digital  Converter. For  a 100  KHz  sine wave  input,  the number 
of samples taken per cycle of the input will be 10  
   (a)  7
   (b)  4
   (c)  3
   (d)  2

1.6  Higher  synchronous  reactance  is  preferred  in  the  present  day  alternators, 
because one can have 
  (a)  reduced sub-transient currents  (b)  reduced harmonic currents 
 (c)  reduced transient currents 
 (d)  higher voltage regulation with load 

1.7  A series R-L-C circuit when excited by a 10V sinusoidal voltage source of variable 
frequency, exhibits resonance at  100 Hz and has  a 3  dB bandwidth of  5 Hz.  The 
voltage across the inductor L at resonance is: 
   (d) 200V 
  (a)  10 V  (b)  100V   (c)  2V

1.8  The RMS value of a half-wave rectified symmetrical square wave current of 2A is: 
  (a)  2A   (b)  1A  (c)  1
   (d)  3A  

1.9  Electodynamic  type  wattmeters  have  large  errors  while  measuring  power  in  ac 
circuits  at low  power  factor  conditions,  since  the  voltage across  and  the  current 
through the 
  (a)  current coil are not in phase  (b)  current coil are not in quadrature 
 (c)  pressures coil are not in phase 
 (d)  pressure coil are not in quadrature 

1.10  The current in the circuit shown in Fig.1.12 is: 
 (a)  5A  (b)  10A 
 (c)  15A  (d)  25A 

1.11  An  overhead  line having  a surge  impedance  of  400   is  connected in  series  with 
an  underground  cable  having  a  surge  impedance  of  100 .  If  a  surge  of  50  kV 
travels  from  the  line  end  towards  the  line-cable  junctions,  the  value  of  the 
transmitted voltage wave at the junction is: 
  (a)  30 kV  (b)  20 kV  (c)  80 kV  (d) -30 kV 

1.12  The load carrying capability of a long AC transmission line is:   
 (a)  always limited by the conductor size   
 (b)  limited by stability considerations   
 (c)  reduced at a low ambient temperatures  
 (d)  decreased by the use of bundled conductors of single conductors 

1.13  Corona losses are minimized when 
 (a)  conductor size is reduced  (b)  smooth conductor is reduced   
 (c)  sharp points are provided in the line hardware   
 (d)  current density in conductors is reduced 

1.14  In a DC transmission line 
 (a)  it  is  necessary  for  the  sending  end  and  receiving  end  to  be  operated  in 
synchronism.   
  (b)  the effects  of inductive  and  capacitive reactances  are greater than in an AC 
transmission line of the same rating.   
  (c)  there are not effects due to inductive and capacitive reactances   
 (d)  power transfer capability is limited by stability considerations.  

1.15  Steady state stability of a power system is the ability of the power system to 
 (a)  maintain voltage at the rated voltage level 
 (b)  maintain frequency exactly at 50 Hz 
 (c)  maintain a spinning reserve margin at all times 
 (d)  maintain synchronism between machines and on external tie lines 

 1.16.  Starting  torque  can  be  obtained  in  the  case  of  a  single  phase  induction  motor 
with identical main and auxiliary windings by connecting 
  (a)  a capacitor across the mains       
 (b)  a capacitor in series with the machine 
 (c)  a capacitor in series with the auxiliary winding       
 (d)  the main and the auxiliary windings in series 

1.17.  Resonant converters are basically used to 
 (a)  generate large peaky voltage  (b)  reduce the switching losses   
 (c)  eliminate harmonics   
 (d)  convert a square wave into a sine wave 

1.18.  A PWM switching scheme is used with a three phase inverter to 
 (a)  reduce the total harmonic distortion with modest filtering 
 (b)  minimize the load on the DC side 
 (c)  increase the life of the batteries 
 (d)  reduce low order harmonics and increase high order harmonics 

1.19  The  following starting method  for an  induction motor  is inferior view of the  poor 
starting torque per ampere of the line current drawn: 
  (a)  Direct line starting   
 (b)  Auto transformer method of starting 
 (c)  Series inductor method of starting       
 (d)  Star-Delta method of starting 

1.20  The color code of a 1 k  resistance is: 
 (a)  black, brown, red     (b)  red, brown, brown   
 (c)  brown, black, red     (d)  black, black, red 

Author	Message
Arpita Groupie Joined: 04Jan2007 Online Status: Offline Posts: 73	Topic: 1999- year EE GATE Paper Posted: 14Feb2007 at 10:27am
	1. This question consists of 20 sub-questions. Each sub-question carries ONE mark. The answers to these sub-questions MUST be written only in the appropriate boxes corresponding to the questions in the first page of the answer book. 1.1 When the plate area of a parallel plate capacitor is increased keeping the capacitor voltage constant, the force between the plates (a) increase (b) decreases (c) remains constant (d) may increase or decrease depending on the metal making up the plates 1.2 Two parallel wires separated by a distance d are carrying a current I in the same direction. The magnetic field along a line running parallel to these wires and midway between them (a) depends upon I (b) is zero (c) depends upon d (d) depends upon the permeability of medium between the wires 1.3 An electromagnetic field is radiated from (a) a stationary point charge (b) a capacitor with a DC voltage (c) a conductor carrying a DC current (d) an oscillating dipole 1.4 As the temperature is increased, the voltage across a diode carrying a diode carrying a constant current (a) increases (b) decreases (c) remains constant (d) may increase or decrease depending upon the doping levels in the junction 10 samples per 1.5 A single channel digital storage oscilloscope uses a 10 bit, 7second Analog-to-Digital Converter. For a 100 KHz sine wave input, the number of samples taken per cycle of the input will be 10 (a) 7 (b) 4 (c) 3 (d) 2 1.6 Higher synchronous reactance is preferred in the present day alternators, because one can have (a) reduced sub-transient currents (b) reduced harmonic currents (c) reduced transient currents (d) higher voltage regulation with load 1.7 A series R-L-C circuit when excited by a 10V sinusoidal voltage source of variable frequency, exhibits resonance at 100 Hz and has a 3 dB bandwidth of 5 Hz. The voltage across the inductor L at resonance is: (d) 200V (a) 10 V (b) 100V (c) 2V 1.8 The RMS value of a half-wave rectified symmetrical square wave current of 2A is: (a) 2A (b) 1A (c) 1 (d) 3A 1.9 Electodynamic type wattmeters have large errors while measuring power in ac circuits at low power factor conditions, since the voltage across and the current through the (a) current coil are not in phase (b) current coil are not in quadrature (c) pressures coil are not in phase (d) pressure coil are not in quadrature 1.10 The current in the circuit shown in Fig.1.12 is: (a) 5A (b) 10A (c) 15A (d) 25A 1.11 An overhead line having a surge impedance of 400 is connected in series with an underground cable having a surge impedance of 100 . If a surge of 50 kV travels from the line end towards the line-cable junctions, the value of the transmitted voltage wave at the junction is: (a) 30 kV (b) 20 kV (c) 80 kV (d) -30 kV 1.12 The load carrying capability of a long AC transmission line is: (a) always limited by the conductor size (b) limited by stability considerations (c) reduced at a low ambient temperatures (d) decreased by the use of bundled conductors of single conductors 1.13 Corona losses are minimized when (a) conductor size is reduced (b) smooth conductor is reduced (c) sharp points are provided in the line hardware (d) current density in conductors is reduced 1.14 In a DC transmission line (a) it is necessary for the sending end and receiving end to be operated in synchronism. (b) the effects of inductive and capacitive reactances are greater than in an AC transmission line of the same rating. (c) there are not effects due to inductive and capacitive reactances (d) power transfer capability is limited by stability considerations. 1.15 Steady state stability of a power system is the ability of the power system to (a) maintain voltage at the rated voltage level (b) maintain frequency exactly at 50 Hz (c) maintain a spinning reserve margin at all times (d) maintain synchronism between machines and on external tie lines 1.16. Starting torque can be obtained in the case of a single phase induction motor with identical main and auxiliary windings by connecting (a) a capacitor across the mains (b) a capacitor in series with the machine (c) a capacitor in series with the auxiliary winding (d) the main and the auxiliary windings in series 1.17. Resonant converters are basically used to (a) generate large peaky voltage (b) reduce the switching losses (c) eliminate harmonics (d) convert a square wave into a sine wave 1.18. A PWM switching scheme is used with a three phase inverter to (a) reduce the total harmonic distortion with modest filtering (b) minimize the load on the DC side (c) increase the life of the batteries (d) reduce low order harmonics and increase high order harmonics 1.19 The following starting method for an induction motor is inferior view of the poor starting torque per ampere of the line current drawn: (a) Direct line starting (b) Auto transformer method of starting (c) Series inductor method of starting (d) Star-Delta method of starting 1.20 The color code of a 1 k resistance is: (a) black, brown, red (b) red, brown, brown (c) brown, black, red (d) black, black, red
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