RRB JE electrical practice paper | RRB JE Electrical

RRB Previous Year Paper / March 15, 2022

Ques.41. “Selsyn” is the trade name of

  1. Synchros
  2. Resolver
  3. Linear
  4. Gyroscope

Answer.1. Synchros

 

Ques.42. Synchro generator and motor is

  1. 3 Phase A.C Device
  2. Single phase A.C device
  3. Two phase A.C device
  4. Single Phase D.C Device

Answer.3. Two phsae A.C device

 

Ques.43. The compensating winding is used in the amplidyne

  1. To increase the current output of the amplidyne
  2. To increase the voltage output of the amplidyne
  3. To reduce the flux setup by the control field
  4. To counterbalance the magnetic field setup by the load current

Answer.2. To increase the voltage output of the amplidyne

 

Ques.44. Which of the following will you choose for high power amplification?

  1. Magnetic amplifier
  2. Electronic amplifier
  3. Ampliydne
  4. D.C generator

Answer.1. Electronic amplifier

 

Ques.45. The bias is used in the magnetic amplifier

  1. To increase the D.C current in the core
  2. To increase the D.C flux in the core
  3. To weaken the A.C flux in the core
  4. To produce an initial amount of D.C saturation to obtain more amplification for weak signals than would be obtained without it

Answer.3. To weaken the A.C flux in the core

 

Ques.46. The power amplification in the magnetic amplifier can be increased

  1. By position feedback
  2. By negative feedback
  3. With a higher inductance of A.C coil
  4. None of these

Answer.4. None of these

 

Ques.47.  A diode is connected in series with the A.C source in the magnetic amplifier

  1. To avoid ripple from the signals
  2. To avoid desaturation of the core due to the negative half cycle
  3. To convert A.C to pure D.C
  4. To suppress high frequencies of source current

Answer.2. To avoid desaturation of the core due to the negative half cycle

 

Ques.48. An electric motor of 5 H.P having an efficiency of 85% is used for 4 hours. If the electrical energy costs Rs.2.00 per unit. Find the cost of using the motor.

  1. Rs.34.304
  2. Rs.30.33
  3. Rs.32.40
  4. Rs.36.42

Answer.1. 34.304

 

Ques.49. A person receives a severe electric shock in which he is subjected to current of 2.5 mA for a time duration of 30 minutes. How many electrons pass through the body of person

  1. 3.67 × 1014 electrons
  2. 4.28 × 1014 electrons
  3. 2.67 × 1014 electrons
  4. 4.68 × 1014 electrons

Answer.4. 4.68 × 1014 electrons

 

Ques.50. A condenser is connected for 0.20 sec across a 220 V supply, the current being kept steady at 0.20 A. Calculate its charge and capacity

  1. 0.04 coulomb and 181.81 µF
  2. 0.08 coulomb and 178.82 µF
  3. 0.12 coulomb and 182.83 μF
  4. 0.02 coulomb and 184.84 µF

Answer.1. 0.04 coulomb and 181.81 µF

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