There are two types of friction. Internal and external friction are types of friction. The coefficient of friction is independent of the force of friction.
2. Calculate the value of the coefficient of friction using the data: F=24 N, Normal force=12 N.
A. 2
B. 4
C. 8
D. 9
Answer: A
The coefficient of friction is the ratio of the friction force and normal force. It is dependent on the smoothness of the surface area.
μ=24÷12=2.
3. If the friction force value is doubled, calculate the new value of the coefficient of friction.
A. 4 times the original value
B. 2 times the original value
C. 7 times the original value
D. Remains the same
Answer: D
The value of the coefficient of friction will not change if the friction force is doubled. It only depends upon the nature of the surface.
4. The frictional force always acts in the _________ direction of motion of the body.
A. Opposite
B. Same
C. Perpendicular
D. Vertical
Answer: A
The friction of force always acts in the opposite direction of the motion of the body. It is a non-conservative force. It helps in the motion of the body.
5. Calculate the coefficient of friction if the angle of inclination is 60°.
A. 2.73
B. 1.73
C. 2.48
D. 1.41
Answer: B
The coefficient of friction is the tangent of the angle of the inclined plane. The value of μ is the tan(60°)=1.73. The coefficient of friction depends on the nature of the surface.
6. Which one of the following is the correct relationship of force?
A. F=μR
B. F=4μR
C. F=3μR
D. F=2μR
Answer: A
The value of the friction force is the product of the coefficient of friction and normal reaction. The correct value is F=μR.
7. Calculate the velocity of the bottom point of the wheel for perfect rolling using the data: r=20 cm, ω=100 rad/sec.
A. 20 m/sec
B. 40 m/sec
C. 60 m/sec
D. 80 m/sec
Answer: A
The velocity of the bottom point of the wheel for perfect rolling is the product of the radius and angular velocity. It is expressed in terms of m/sec.
V = r×ω = .2×100=20 m/sec.
8. The coefficient of adhesion is maximum when rails are dusty.
A. True
B. False
Answer: B
The coefficient of adhesion is maximum when rails are dry. The coefficient of adhesion depends on the nature of the material.
9. Calculate the value of the coefficient of adhesion for dusty rails if the value of the coefficient of adhesion for dry rails is .55.
A. 0.65
B. 0.89
C. 0.97
D. 0.48
Answer: D
The value of the coefficient of adhesion for dusty rails is .48. The value of the coefficient of adhesion for dry rails is maximum.
10. Calculate the value measured by Moving Iron when a sinusoidal voltage signal V(t) = √2sin(3ωt) is applied to it.
A. 2 V
B. 1 V
C. 3 V
D. 4 V
Answer: B
Moving iron instrument measures the r.m.s value of the input signal. The r.m.s value of the sinusoidal signal is
√2÷√2 = 1 V.
11. The value of area under a velocity-time graph is _________
A. Acceleration
B. Displacement
C. Force
D. Momentum
Answer: B
The value of the area under a velocity-time graph is displacement. The velocity is the ratio of displacement and time.
12. The value of area under acceleration-time graph is _________
A. Velocity
B. Displacement
C. Force
D. Impulse
Answer: A
The value of the area under an acceleration-time graph is velocity. The acceleration is the ratio of velocity and time.
13. The value of area under force-time graph is _________
A. Reaction
B. Change in momentum
C. Force
D. Torque
Answer: B
The value of the area under a force-time graph is a change in momentum. The force is the ratio of change in momentum with respect to time.
14. Full form of HVDC is _________
A. High Voltage Direct Current
B. High Voltage Distribution Combination
C. High-Value Direct Current
D. High-Value Distribution Combination
Answer: A
The full form of HVDC is High voltage direct current. HVDC is more preferred than HVAC because of minimum losses.
15. Full form of HVAC is _________
A. High Voltage Alternative Current
B. High Voltage Alternating Current
C. High-Value Alternating Combination
D. High-Value Alternative Counter
Answer: B
The full form of HVAC is a High voltage alternating current. It is mostly preferred for smaller distances. HVAC has higher losses than HVDC.
16. Full form of SVC is ___________
A. Static Var Compensator
B. Static Variable Counter
C. State Value Counter
D. Static Value Compensator
Answer: A
The full form of SVC is Static Var Compensator. It is a FACTS controller used for reactive power compensation. It maintains the voltage profile.
17. Full form of STATCOM is ________
A. Static Synchronous Counter
B. Static Synchronous Compensator
C. State Synchronized Compensator
D. State System Counter
Answer: B
The full form of STATCOM is a Static synchronous compensator. It is a voltage source converter. It maintains the voltage profile of the system. It is a FACTS controller.
18. The circuit which operates signals is called as ___________
A. Track circuit
B. Fellow circuit
C. Ground circuit
D. Unit circuit
Answer: A
The circuit which operates signals is called a track circuit. Its supply consists of low AC or DC voltage supply. Running rail is used as the return line for the track circuit.
19. SVC is used to maintain the power factor above __________
A. .2
B. .5
C. .8
D. .6
Answer: C
SVC is used to maintain the power factor above 8.
SVC stands for static var compensator. It is the FACTS controller used for reducing the harmonics of the system. It is used for reactive power compensation.
20. Which is the most severe type of fault?
A. LL
B. LLG
C. LLL
D. LLLG
Answer: D
LLLG fault is the most severe type of fault. The order of severity is maximum for LLLG fault. LG fault is more severe at the generator terminals.
21. Skin effect increases at higher frequencies.
A. True
B. False
Answer: A
Skin effect increases with the increase in frequency. The value of skin depth decreases with the increase in frequency.
22. If induction motor air gap power is 11 KW and mechanically developed power is 2 KW, then rotor ohmic loss will be _________ KW.
A. 8
B. 10
C. 9
D. 11
Answer: C
Rotor ohmic losses are due to the resistance of armature windings. Net input power to the rotor is equal to the sum of rotor ohmic losses and mechanically developed power. Rotor ohmic losses = Air gap power – Mechanical developed power = 11-2 = 9 KW.
23. If induction motor rotor power is 26 KW and gross developed power is 21 KW, then rotor ohmic loss will be _________ KW.
A. 5
B. 6
C. 7
D. 8
Answer: A
Rotor ohmic losses are due to the resistance of armature windings. Net input power to the rotor is equal to the sum of rotor ohmic losses and mechanically developed power.
Rotor ohmic losses=Air gap power-Mechanical developed power
=26-21=5 KW.
24. Calculate the active power in 14 μH inductors if the THD value is 58.1%.
A. 5 W
B. 9 W
C. 4 W
D. 0 W
Answer: D
The inductor is a linear element. It only absorbs reactive power and stores it in the form of oscillating energy. The voltage and current are 90° in phase in the case of the inductor so the angle between V & I is 90°.
P = VIcos90° = 0 W.
25. Calculate the power factor using the data: P=15 W, S=25 VA.
A. 0.5
B. 0.9
C. 0.4
D. 0.6
Answer: D
The power factor is the ratio of active power and apparent power. The value of the power factor is
P÷S=15÷25=.6.
26. Calculate the active power in a 56 μF capacitor if the VRF value is 5.1%.
A. 6 W
B. 0 W
C. 9 W
D. 2 W
Answer: B
The capacitor is a linear element. It only absorbs reactive power and stores it in the form of oscillating energy. The voltage and current are 90° in phase in the case of the capacitor so the angle between V & I is 90°.
P = VIcos90° = 0 W.
27. Calculate the apparent power using the data: P=3 W, Q=4 VAR.
A. 5 VA
B. 6 VA
C. 9 VA
D. 2 VA
Answer: A
The apparent power is the product of the voltage and current conjugate phasor. The value of apparent power is (9+16).5 = 5 VA.
28. Calculate the value of impedance using the data: R=2 Ω, XL=4 Ω.
A. 5.5 Ω
B. 5.4 Ω
C. 2.5 Ω
D. 4.4 Ω
Answer: D
The value of impedance is
{(R)2+(XL)2).5 = (4+16).5 = 4.4 Ω.
It is the total impedance offered by an AC circuit. It is expressed in Ω.
29. Which type of grounding is used to suppress the capacitive effect?
A. Solid grounding
B. Reactance grounding
C. Resistance grounding
D. Peterson coil
Answer: D
Peterson coil or resonance grounding is used to suppress the capacitive effect. The frequency in resonance grounding is ω2 = 1÷(3LC)
30. Electric trains are of two types.
A. True
B. False
Answer: A
Mainline trains and suburban trains are the two types of trains. They run on fixed rails. They are powered by electricity.
31. The shape of pantograph collector is __________
A. Square
B. Pentagon
C. Circle
D. Hexagon
Answer: B
The shape of the pantograph collector is a pentagon. It has a conducting strip that is pressed against contact wire with the help of springs.
32. There are typically three types of the pantograph.
A. True
B. False
Answer: A
There are typically three types of the pantograph. Open frame, faiveley, and crossed arm are typically three types of pantograph. The function of the pantograph is to maintain pressure and prevent vertical vibrations.
34. Full form of EMU is ________
A. Electronics Multiple Unit
B. Electrical Multiple Unit
C. Electrical Multiple Usage
D. Electrical Multiple User
Answer: B
The full form of EMU is Electrical Multiple Unit. The trains having motor coaches and trailer coaches are known as EMU trains. They provide flexibility.
35. Who is known as the Father of Indian Railways?
A. Lord Dalhousie
B. Lord Ripon
C. Lord Boult
D. Lord Hero
Answer: A
Lord Dalhousie is known as the father of the Indian Railways. The first railway line connecting Bombay with Thane was laid in 1853.
36. Who built the first train?
A. Richardson
B. Rampa
C. Richard Trevithick
D. John Carry
Answer: C
Richard Trevithick built the first train in 1804. It was a steam locomotive train that used to carry 10 tonnes of iron from one place to another.
37. Who built the first bullet train?
A. Hideo Rampa
B. Hideo Shima
C. Hideo Carry
D. Hideo Stokes
Answer: B
Hideo Shima built the first bullet train. He was a Japanese engineer. He was born in 1901 and died in 1998. He was the man behind the concept of a bullet train.
38. The supply conductor in electric trains is also known as ____________
A. Contact Wire
B. Contact Distance
C. Contact Direction
D. Supply Wire
Answer: A
The supply conductor in electric trains is also known as Contact wire. Driving motor and power modulators are housed in the locomotive.
39. Calculate the value measured by PMMC when a sinusoidal voltage signal is applied to it.
A. 15 V
B. 0 V
C. 16 V
D. 18 V
Answer: B
PMMC instrument measures the average of the input signal. The sinusoidal voltage signal is symmetric about the origin. The average value measured by PMMC is zero.
40. Calculate the value measured by Moving Iron when a sinusoidal voltage signal V(t)=20sin(ωt) is applied to it.
A. 14.14 V
B. 20.15 V
C. 16.18 V
D. 22.18 V
Answer: A
Moving iron instrument measures the r.m.s value of the input signal. The r.m.s value of the sinusoidal signal is
20÷√2=14.14 V.
41. Full form of PMMC is __________
A. Permanent Magnet Moving Coil
B. Premature Magnet Moving Coil
C. Permanent Magnet Motion Coil
D. Peterson Magnet Motion Coil
Answer: A
The full form of PMMC is Permanent Magnet Moving Coil. It measures the average value of the applied input signal.
42. Fuel used in the train is _________
A. Diesel
B. Kerosene
C. Petrol
D. Ice
Answer: A
The fuel used in the train is Diesel. Diesel fuel in trains provides more efficiency and more economy. It is more economical than air travel.
43. How much fuel does a train use per Km?
A. 7.85 L/Km
B. 7.97 L/Km
C. 6.59 L/Km
D. 7.15 L/Km
Answer: B
The average fuel consumed by a train is 7.97 L/Km. Consumption is the same for passenger and cargo trains.
44. Which motor is used in the electric train?
A. DC shunt motor
B. DC series motor
C. Synchronous motor
D. Stepper motor
Answer: B
DC series motor is used in electric trains. They provide a high starting torque. DC series motor is a universal motor that can run on DC as well as on AC.
45. Calculate the minimum time period for ASCI using the data: R=1 kΩ, C=1 μF.
A. 4 msec
B. 8 msec
C. 5 msec
D. 3 msec
Answer: A
The minimum time period for ASCI is a
4×R×C = 4×1×1×.001 = 4 msec.
The total time is the sum of charging and discharging time.
