Wednesday, August 10, 2016

Lucknow Metro Question



Q1:- Function of surge absorber is 

  1. to protect apparatus under short circuit fault
  2. exactly same as lighting arrestor
  3. to divert surge to earth 
  4. to reduce the steepness of wave front of a surge 
ANSWER:- 4



Q2:- The rotor of an I.M. rotates due to 

  1. interaction b/w the stator magnetic field and field due to induction current in the rotor 
  2. interaction b/w the stator voltage and rotor voltage 
  3. p[rime mover connected to the motor 
  4. interaction b/w the i/p supply frequency and rotor voltage frequency 
ANSWER:-1



Q3:- The resistance R offered by a conductor varies 

  1. directly as its cross sectional area and the resistivity of the material and inversely as its length 
  2. directly as its length and cross sectional area of the material and inversely a sits resistivity 
  3. directly as its resistivity and length of the material and inversely as its cross sectional area 
  4. directly as the temperature and cross sectional area of the material and inversely as its length 
ANSWER:-3



Q4:- Safety factor of insulator is the ratio of 
  1. puncture strength to flash over voltage 
  2. flash over voltage to puncture strength 
  3. flash over voltage to line voltage 
  4. line voltage to flash over voltage 
ANSWER:-1



Q5:- Power factor can be improved by 
  1. static capacitor 
  2. synchronous condenser
  3. phase advancers 
  4. all of the above 
ANSWER:-4


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