SEMESTER - IV JAN2018
If a slot consists of one coil side then the winding is called.......
a) Double layer winding
b) Full pitch winding
c) Single layer winding
d) Short pitch winding
A capacitor start, capacitor run single phase induction Inotor is basically a........
a) AC series b) DC series motor
c) 2 phase induction motor
d) 3 phase induction tnotor
The starting torque of' a capacitor start lü0tor is —
c) Same as rated torque
d) More than rated torque
The starting capacitor of a single phase motor is......
a) Electrolytic capacitor
b) Ceramic capacitor
c) Paper capacitor
d) None of the above.
The motor used in household refrigerators is
a) series Inotor
b) DC shunt motor
c) Universal Inotor
d) Single phase induction tnotor.
A capacitor start single phase induction motor will usually have a pov.er thctor of.......
b) 0.8 leading
c) 0.6 leading
d) 0.6 lagging
The short corning of repulsion motor is —
a) Variation of speed with load
b) Low power lhctor
c) Il'cndcncy to spark at brushes d) All of these
A ceiling fan, of 1 nun sweep will have motor rating or.......
a) 10 to 1 5 watts
b) 50 to 70 watts
c) 120 to 1 80 watts
b) 250 to 500 watts.
Which of the following applications would need the smallest size or motor?
a) Domestic motor
b) Electric clock
c) Table fan
d) Sewing machine
Which of the following is not a bio-mass source?
a) Gobar gas
d) Nuclear energy
The source of energy of the sun is
a) Nuclear fission
b) Chemical reaction
c) Nuclear fusion
d) Photoelectric effect
Which motor would you select for vacuum cleaners?
a) Universal motor
b) Repulsion motor
c) Hysteresis motor
d) Reluctance motor.
The advantage of salient poles in an alternator is.......
a) Reduce noise
b) Reduced windagc loss
c) Adoptability to low and medium speed operation
d) Reduce bearing loads and noise.
Major share of power generated in India is through which means-
a) Hydroelectric power plants
b) Nuclear power plants
c) Thermal power plants
d) Gas turbine power plants
A three phase alternator has a phase sequence of RYB for its three output voltages, for clockwise rotation. Now if the alternator is rotated anticlock wise. the phase sequence will be
a) RYB b) RBY
c) BYR d) None of these
In an alternator, voltage drops occurs in......
a) Armature resistance only
b) Armature resistance and leakage reactance
c) Armature resistance, leakage reactance and armature reaction
d) Annaturc resistance, leakage reactance. armature reaction and earth connections.
The power Factor of' an alternator depends on —
a) Load b) Speed of rotor
c) Core losses d) Armature losses
The frequency of voltage generated by an alternator having 8 poles and rotating at 250 rpm is........
a) 60 Hz. b) 50 Hz
c) 25 Hz d) 16 2/3Hz
A winding is having number of slots is greater than munber of poles. then this winding is called-
a) Concentrated winding
b) Distributed winding
c) Full pitch winding
d) Integrated slot winding
Synchronous Inotor can operate at.......
a) Lagging power factor only
b) Leading power factor only
c) Unity power factor only
d) Lagging, leading and unity power factor only
The damping winding in a synchronous motor is generally used
a) To provide starting torque only
b) To reduce noise lcvcl
c) To reduce eddy currents
d) To prevent hunting and provide the starting torque
The back emf set up in the stator of a synchronous motor will depend on
a) Rotor speed only
b) Rotor excitation only
c) Rotor excitation and rotor speed
d) Coupling angle. rotor speed and excitation
In a synchronous motor, damper winding is provided to
a) Stabilize rotor Inotion
b) Suppress rotor oscillations
c) Develop necessary starting torque
d) Both (a) & (c)
Advantagc of hydro-elcctric power station is........
a) Low operating cost
b) Free from pollution probletns
c) No fuel transportation problems
d) All of these
An Auto-transformer (which has only one winding) may be used as a........
a) Step-Up Transformer
b) Step-Down Transformer
c) Both (a) & (b)
d) None of the above
26. In an Auto transformer, The Primary and Secondary are ....... Coupled
a) Only Magnetically
b) Only Electrically
c) Magnetically as well as Electrical
d)None of these
The nominal ratio for a current transformer is given by
a) (Rated primary winding current)/ (Rated secondary winding current)
b) (Number of turns in the primary winding) / (Number of turns in the secondary winding)
c) (Number of turns in the secondary winding)/ (Number of turns in the primary winding)
d) (Rated secondary winding current) / (Rated primary winding current)
The transformer ratio of the transformer depends upon the
a) Exciting current
b) Secondary current
c) Power factor of secondary circuit
d) All of these
Radiant efficiency of the luminous source depends on
a) Shape of the source
b) Temperature of the source
c) Wavelength of light rays
d) All of these
Carbon arc lamps arc commonly used in.........
a) Domestic lighting
b) Street lighting
c) Cinema projectors
The unit of solid angle is.........
a) Solid angle b) Radian
c) Steradian d) Candela
Candela is the unit of ..........
a) Luminous flux
b) Luminous intensity
d) None of these
The unit of' Iuminous flux is ......
a) Steradian b) Candela
Luminous efficiency of a fluorescent tube is .......
a) 5- 10 lumens/watt
b) 15-20 lumens/watt
c) 30 - 40 lumens/watt.
d) 60-65 lumens/watt.
One lumen per square meter is the same as..........
a) One lux
b) One candela
c) One foot candle
d) One lumen meter
The frequency or (lickers in a fluorescent lamp at 220 V, 50 Hz supply will be.......
a) 25 per second
b) 50 per second
c) 100 per second
d) 220 per second
One that is based on forward biased PN junction is......
a) Photo diode. b) LED
c) Photo voltaic cell
d) Both (a) & (b)
Photo diode is used for detection of .........
a) Visible light
b) Invisible light
c) No light
d) Both (a) & (b)
Color of light emitted by LED depends on......
a) Its forward bias
b) Its reverse bias
c) Forward current
d) Semiconductor material
The earth wire should not be thinner than a.......
a) 20 SWG wire b) 16 SWG wire
c) 10 SWG wire d) 8 SWG wire
In the sound is produced by horn due to .......
b) Vibrating diaphragm
c) Moving coil
d) Oscillating coil
In a constant power type load
a) Torque is proportional to speed b) Torque is proportional to square of speed
c) Torque is inversely proportional to speed
d) Torque is independent or speed.
The frame of an induction motor is usually made of.......
a) Silicon steel b) Cast iron
c) Aluminicun d) Copper
Slip rings arc usually made of......
c) Phosphor bronze
In a hydro-electric plant a conduct system for taking water from the intake works to the turbine is known as.....
a) Dam b) Reservoir
c) Penstock d) Surge tank
The shaft of an induction motor is made from.........
a) High speed steel
b) Stainless steel
c) Carbon steel
d) Cast iron
In a induction motor, no-load slip is generally.........
a) Less than I percent b) 5 percent
c) 2percent d) 4 percent
The most common type of ac motor is the.........
a) Single phase induction motor b) Two-phase induction motor
c) Three-phasc induction motor
d) Two-phase squirrel-cage motor
A single-phase induction motor ...........
a) Is self-starting
b) Operates at a fixed speed
c) Is less reliable than a three-phase synchronous motor
d) None of the above