RRB JE Previous solved paper set 8
19. Which of the following motors is used in tape recorders
A. Hysterisis motor
B. Reluctance motor
C. Capacitor run motor
D. Universal motor
Ans. A.
20. Slip ring for induction motors are made up of
A. cobalt steel
B. aluminium
C. carbon
D. phosphor bronze
Ans. D.
21. A transformer is working at its maximum efficiency. Its iron loss is 1 kW. Its copper loss will be
A. 0.2 kW
B. 0.25 kW
C. 0.5 kW
D. 1 kW
Ans. D.
22. For arc heating, electrodes are made up of
A. Copper
B. Aluminium
C. Graphite
D. Tungsten
Ans. C.
23. Sodium lamps are used in
A. Reading rooms
B. Street Lights
C. Auditorims
D. Libraries
Ans. D.
24. The fuse wire is made up of
A. Nichrome
B. Lead-tin alloy
C. Copper
D. Tungsten
Ans. B.
25. There are ………… Number of modulation techniques.
A. 1
B. 2
C. 3
D. 4
Ans. C.
26. In frequency modulation
A. amplitude of carrier wave remains the same
B. frequency of carrier wave remains constant
C. both frequency and amplitude of carrier waves vary
D. signal gets distorted.
Ans. A.
27. In mercury are rectifier, mercury is used as
A. cathode
B. conducting medium
C. ionizing medium
D. electron accelerator
Ans. A.
28. For single phase rotary converters, when the power factor is unity, the ac to dc current ratio will be
A. 1.0
B. 0.707
C. 1.4
D. 0.5
Ans. C.
29. When a material becomes a superconductor, its resistivity becomes
A. very small
B. zero
C. about 10% of normal value
D. about 20% of normal value
Ans. B.
30. The inputs of logic gate are 0. The output is 1. The gate is
A. NAND or XOR
B. OR or XOR
C. AND or XOR
D. NOR or Ex-NOR
Ans. D.
31. Octal number 12 is equal to decimal number
A. 9
B. 10
C. 11
D. 12
Ans. B.
32. The output of a NOR gats is HIGH if …………….
A. all inputs are high
B. any input is high
C. any input is low
D. all input are low
Ans. D.
33. A circuit that uses n amplifier with passive filter elements is called a (n)
A. relaxation osillator
B. signal generator
C. active filter
D. differential amplifier
Ans. C.
34. Ionization within a P-N junction causes a layer on each side of the barrier called the
A. junction
B. depletion region
C. barrier voltage
D. forward voltage
Ans. B.
35. Cup-and-cone type fracture occurs in the case of
A. Cast iron
B. Round specimen of ductile metals
C. Tough steel
D. Soft brass
Ans. B.
36. Liquid limit of a soil indicates its
A. Compressibility
B. Permeability
C. Optimum moisture
D. Shear strength
Ans. A.