RRB JE electrical practice paper | RRB JE Electrical

Ques.21. Determine the temperature coefficient of resistance of material used in a resistor, if the resistance at 25°C is 50 Ω and 70°C is 57.2 Ω

  1. 0.007
  2. 0.005
  3. 0.003
  4. 0.008

Answer.2. 0.005

 

Ques.22. The resistance of a certain conductor is 18.6 ohms. Find the resistance of another conductor of the same material if its length is the five times the area is three times

  1. 21.0 Ohms
  2. 27.0 Ohms
  3. 29.0 Ohms
  4. 31.0 Ohms

Answer.4. 31.0 Ohms

 

Ques.23. Which of the following Indian Standards deal with Inductor motors?

  1. IS: 2026
  2. IS: 325
  3. IS:2028
  4. IS: 3456

Answer.2. IS: 325

 

Ques.24. The electric strength of the air barometric pressure of 76 cm and 25°C is

  1. 30 kV/meter
  2. 21.1 kV r.m.s/cm
  3. 21.1 kV r.m.s/cm
  4. 21.1 kV/cm

Answer.2. 21.1 kV r.m.s/cm

 

Ques.25. The critical value of surge impedance of large transmission line is

  1. 50 ohm
  2. 500 ohm
  3. 75 ohm
  4. 1000 ohm

Answer.2. 500 ohm

 

Ques.26. The surge impedance of telephone line is

  1. 75 ohm
  2. 600 ohm
  3. 500 ohm
  4. 50 ohm

Answer.1. 75 ohm

 

Ques.27. If A, B, C, D are constants of the medium transimission line, which of the following relation is correct

  1. AB − CD = −1
  2. AB + BD = 1
  3. BC − AD = −1
  4. AC − BD = 1

Answer.3. BC – AD = −1

 

Ques.28. What is the unit of resistivity?

  1. Ohm-m
  2. Mho-m
  3. Henry
  4. None of these

Answer.1. Ohm-m

 

Ques.29. The surge impedance of an Underground cable is

  1. 60 to 100 ohm
  2. 40 to 600 ohms
  3. 40 to 60 ohms
  4. 30 to 75 ohms

Answer.3. 40 to 60 ohms

 

Ques.30. As the transmission voltage increase the volume of the conductor is

  1. Increase
  2. Decrease
  3. Will not change
  4. Will increase in random Manner

Answer.2. Decrease

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