Electric Illumination MCQ PDF

61. In high pressure mercury vapor lamps

(a) the main electrodes are made of tungsten wire in the form of helix.
(b) the choke is provided to limit the current to a safe value.
(c) in addition to two main electrodes a starting (auxiliary) electrode is connected through a high resistance .
(d) all of the above.

62. The luminous efficiency of high pressure mercury vapor lamps ranges from lumens per watt.

(a) 30 to 40
(b) 60 to 100
(c) 100 to 150
(d) 250 to 400

63. In mercury iodide lamps

(a) a number of iodides are added, in addition to mercury, to fill up the gaps in the light spectrum.
(b) a separate ignition device, in addition to the choke, is provided.
(c) both (a) and (b).
(d) none of the above.

64. Mercury iodide lamps

(a) are similar in construction to high pressure mercury vapor lamps.
(b) have luminous efficiency of the order of 80 lumens per watt.
(c) are suitable for applications in the field of floodlighting, industrial lighting and public lighting.
(d) all of the above.

65. Which of the following lamps is a cold cathode lamp ?

(a) Sodium vapor lamp.
(b) Neon lamp.
(c) Mercury vapor lamp.
(d) None of the above.

66. Neon lamps

(a) are of the size of ordinary incandescent lamps.
(b) have power consumption of the order of 5 watts.
(c) are used as indicator lamps, night lamps, for determination of polarity of dc mains.
(d) all of the above.

67. In neon signs argon gas is used to give

(a) red color.
(b) blue color.
(c) pink color.
(d) green color.

68. In neon signs, neon with a mixture of mercury is used to give

(a) blue color.
(b) green color.
(c) pink color.
(d) yellow color.

69. The electrodes of neon tube work at

(a) very low temperatures.
(b) ordinary voltage.
(c) 2 kV to 6 kV.
(d) 33 kV.

70. Neon tubes are widely used for

(a) advertising.
(b) indoor lighting.
(c) road signaling.
(d) airport lighting.

71. The vapor discharge tube used for domestic light has

(a) one filament.
(b) two filaments.
(c) four filaments.
(d) no filament.

72. The fluorescent tube is coated from inside with a thin layer of fluorescent material in the form of powder in order to

(a) absorb invisible ultraviolet rays and radiate visible rays.
(b) improve the appearance.
(c) reduce glare.
(d) improve life.

73. A stabilizing choke is connected in the fluorescent tube circuit so as to

(a) reduce the flicker.
(b) act as a ballast in operating conditions and provide a voltage impulse for starting.
(c) act as a starter.
(d) avoid radio-interference.

74. A capacitor is connected across the fluorescent tube circuit in order to

(a) eliminate the noise.
(b) limit the current.
(c) improve the power factor of the tube circuit.
(d) all of the above.

75. Which of the following is present inside the fluorescent tube ?

(a) Helium and oxygen.
(b) Argon and neon.
(c) Argon and carbon dioxide.
(d) Mercury vapor.

76. In a fluorescent tube, a ballast resistance is connected in series with the choke

(a) when the tube is operated on dc supply.
(b) when the tube is operated on ac supply.
(c) to reduce radio-interference.
(d) to reduce stroboscopic effects.

77. For operation of fluorescent tube on dc supply the additional device incorporated in the tube circuit is a

(a) transformer.
(b) resistor.
(c) inductor.

78. The light of fluorescent tube appears cooler than that from an incandescent lamp. This is due to the fact that

(a) the tube consumes less power.
(b) surface area of tube is larger than that of the incandescent lamp.
(c) tungsten is not used in the tube .
(d) none of the above.

79. Sometimes the wheels of the rotating machinery in fluorescent tube lighting, appear to be stationary . This is due to

(a) luminescence effect.
(b) light fluctuations.
(c) stroboscopic effect.
(d) all of the above.

80. The flicker effect of fluorescent lamps is more pronounced at

(a) lower voltages.
(c) higher frequencies.
(b) higher voltages.
(d) lower frequencies.

81. The frequency of flickers in a fluorescent tube operating at 220 V, 50 Hz supply is

(a) 200 per second.
(b) 100 per second.
(c) 50 per second
(d) 25 per second.

82. Radio-interference from a fluorescent tube can be reduced by

(a) eliminating choke.
(b) connecting a small capacitor across starter terminals.
(c) putting two tubes in parallel.
(d) any of the above.

83. In a mercury vapor lamp light, red objects appear black. This is on account of

(a) color mixing.
(b) high wavelengths of red color.
(c) absence of red light from lamp radiations.
(d) absorption of red light by the lamp.

84. Blinking of a fluorescent tube may be on account of

(a) low circuit voltage.
(b) loose contact.
(c) defective starter.
(d) any of the above.

85. The cost of a fluorescent tube is more than that of an incandescent lamp on account of

(a) more components in the tube.
(b) more quantity of glass in the tube.
(c) more labor required.
(d) all of the above.

86. The life of a fluorescent tube is affected by

(a) low voltage.
(b) high voltage.
(c) frequency of switching and blinking.
(d) all of the above.

87. The disadvantage(s) of fluorescent tubes in comparison to filament lamps is/are

(a) high cost.
(b) noise in choke.
(c) stroboscopic effect.
(d) all of the above.

89. The ratio of radiant heat produced by a fluorescent tube and that by a filament lamp of the same rating is

(a) 0.2
(b) 0.35
(c) 0.6
(d) 0.75

90. The lamp that cannot sustain much voltage fluctuations is

(a) sodium vapor lamp.
(b) mercury vapor lamp.
(c) incandescent lamp.
(d) mercury iodide lamp.

91. The lamp that gives nearly ultraviolet light is

(a) carbon arc lamp.
(b) vacuum type filament lamp.
(c) argon gas filled filament lamp.
(d) all of the above.

92. Power factor is highest in case of

(a) sodium vapor lamp.
(b) mercury vapor lamp.
(c) incandescent lamp.
(d) neon lamp.

93. The lamp which gives nearly monochromatic light is

(a) sodium vapor lamp.
(b) mercury vapor lamp.
(c) tungsten filament lamp.
(d) fluorescent tube.

94. The lamp that does not have separate choke is

(a) mercury vapor lamp.
(b) sodium vapor lamp.
(c) fluorescent tube.
(d) all of the above.

95. For the same wattage the lamp that will produce minimum radiant heat is

(a) sodium vapor lamp.
(b) fluorescent lamp.
(c) tungsten filament lamp.
(d) mercury vapor lamp

96. The lamp/tube preferred for air-conditioned spaces is

(a) sodium vapor lamp.
(b) mercury vapor lamp.
(c) fluorescent tube.
(d) GLS lamp.

97. The lamp that causes radio-interference is

(a) fluorescent tube.
(b) halogen lamp.
(c) mercury vapor lamp.
(d) all of the above.

98. The lamp that cannot be used for dimming is

(a) cold cathode lamp.
(b) fluorescent lamp.
(c) GLS lamp.
(d) all of the above.

99. Which of the following application does riot require ultraviolet lamps ?

(a) Aircraft cockpit dashboard lighting.
(b) Blue print machines.
(c) Car lighting.
(d) None of the above.

100. Floodlighting is not used for

(a) industrial purposes.
(b) advertising purposes.
(c) aesthetic purposes.
(d) any of the above.