- Technical Blog From My Notebook

Sunday, January 13, 2019

RRB JE Previous questions

RRB 28th August Shift 2

1. For an ideal gas the value of Joule Thomson coefficient is
A. Zero B. 0.5
C. Unity D. Infinite
Ans. A.
2. Perpetual motion machine of second kind violates the
A. First law of thermodynamics
B. Kelvin-plank statement
C. Clausius statement
D. Third law of thermodynamics
Ans. B.
3. The ratio of thermal conductivity to electrical conductivity is equal to
A. Prandtl number B. Schmidt number
C. Lorentz number D. Lewis number
Ans. C.
4. The effectiveness of a fin will be maximum in a environment with
A. Free convection
B. Forced convection
C. Radiation
D. Convection and radiation
Ans. A.
5. With increasing temperature of intake air, IC engine efficiency
A. Decreases
B. Increases
C. Remains same
D. Depends on other factors
Ans. A.
6. Thermal efficiency of CI engine is higher than that of SI engine due to
A. Fuel used
B. Higher compression ratio
C. Constant pressure heat addition
D. Lower compression ratio
Ans. B.
7. The float in the carburettor of a petrol engine controls
A. Flow rate of air
B. Flow rate of fuel
C. Flow rate of air-fuel mixture
D. Level of the petrol in the float chamber
Ans. D.
8. Angle between the face and flank of the single point cutting tool is known as
A. Rake angle B. Clearance angle
C. Lip angle D. Point angle
Ans. C.
9. Which of the following is a cutting tool material
A. High speed steel B. Mild steel
C. Cost iron D. Galvanized steel
Ans. A
10. In milling machine, the cutting tool is held in position by
A. Chuck B. Spindle
C. Arbor D. Tool holder
Ans. C.
11. Collapsible tooth paste tubes are manufactured by
A. Direct extrusion
B. Piercing
C. Impact extrusion
D. Indirect extrusion
Ans. C.
12. Sprue in casting refers to
A. Gate B. Runner
C. Riser D. Vertical passage
Ans. D.
13. In arc welding, arc is created between the electrode and work by
A. Flow of current
B. Voltage
C. Material characteristics
D. Contact resistance
Ans. D.
14. Preheating of work piece is essential in welding
A. High speed steel
B. Stainless steel
C. Cast iron
D. Aluminium
Ans. C.
15. An ideal voltage source should have
A. large value of emf
B. small value of emf
C. zero source resistance
D. infinite source resistance
Ans. C.
16. Which bulbs operates on lowest power
A. Night bulb B. Neon bulb
C. GLS bulb D. Torch bulb
Ans. D.
17. Electrode in not consumed in the case of
A. TIG welding
B. MIG welding
C. Gas welding
D. Resistance welding
Ans. A.
18. DC generator are installed near the load centres to reduce.
A. iron losses
B. line losses
C. sparking
D. corona losses
Ans. B.
19. In a DC motor, constant torque is produced due to
A. rotor laminations B. end plates
C. pole shoes D. commutator
Ans. D.
20. Which of the following is not a part of transformer.
A. Conservator B. Buccholz Relay
C. Exciter D. Breather
Ans. C.
21. An induction motor is
A. self starting with zero torque
B. self starting with high torque
C. self starting with low torque
D. non self starting
Ans. C.
22. The term “cogging” is associated with
A. three phase transformer
B. compound generators
C. DC series motor
D. Induction motors
Ans. D.
23. The speed of universal motor is generally reduced by using
A. gear trains B. V-belts
C. brakes D. chains
Ans. A.
24. A thermal protection switch can protect against
A. short circuit B. temperature
C. over load D. Variable load
Ans. C.
25. In a bipolar transistor which current is largest
A. collector current
B. base current
C. emitter current
D. base or emitter current
Ans. C.
26. The word enhancement mode is associated with
A. tunnel diode B. MOSFET
C. photodiode D. varactor diode
Ans. B.
27. Which of the following has highest resistivity?
A. Mica B. Paraffin
C. Air D. Mineral oil
Ans. C.
28. Power diodes are generally
A. silicon diodes
B. germanium diodes
C. carbon diodes
D. carbon or germanium diodes
Ans. A.
29. The depletion layer width of junction
A. decreases with light doping
B. is independent of applied voltage
C. increases under reverse bias
D. increases with heavy doping
Ans. C.
30. For mercury arc rectifiers, the anode is usually made up of
A. aluminium B. graphite
C. tungsten D. copper
Ans. B.
31. For effective modulation, the degree of modulation should
A. small
B. never exceed 100%
C. be large
D. always more than 100%
Ans. B.
32. Which of them radiates emission?
C. Both LCD and LED
D. Neither LCD nor LED
Ans. A.
33. Binary 101010 is equivalent to decimal number
A. 24 B. 42
C. 64 D. 44
Ans. B.
34. The number of valence electrons in donor impurity are
A. 1 B. 3
C. 5 D. 7
Ans. C.
35. A prismatic beam has uniform
A. Depth B. Width
C. Strength D. Cross-section
Ans. D.
36. A well graded soil has a coefficient of curvature between
A. 10 to 12 B. 7 to 9
C. 4 to 6 D. 1 to 3
Ans. D.
37. How is the deflection in RC beams controlled as per IS : 456?
A. By using large aspect ratio
B. By using small modular ratio
C. By controlling span/depth ratio
D. By moderating water-cement ratio
Ans. C.
38. A steel beam supporting loads from the floor slab as well as from wall is termed as
A. Stringer beam
B. Lintel beam
C. Spandrel beam
D. Header beam
Ans. C.
39. The dimensions of dynamic viscosity μ are
A. ML–1 T–2 B. ML–1 T–1
C. MLT–2 D. M°L°T°
Ans. B.
40. The representative fraction 1/2500 means that the scale 1 cm is equal to
A. 0.25 m B. 2.5 m
C. 25 m D. 2.5 km
Ans. C.

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