RRB JE Electrical One Liner Questions and Answers series Part -2

 As discussed in previous Part let us continue forward 

51. Visible wavelength range is 400 nm to 700 nm.

52. Total light emmited by a light source in all directions is called Luminous flux and unit of Luminous flux is Lumen.

53. Light emmited in particular direction by light source is called Luminous intensity and unit of Luminous intensity is Candela.

54. When light from light source falls on particular surface that light amount per unit area is called illuminance and unit of illuminance is Lux.

55. Amount of light reflects back to observer eyes is called luminance and unit of luminance is Candela per meter square. Another name of luminance is brightness.

56. Watt is the amount of energy a light source takes or consumes to produce the light.

57. Total amount of light emmited by a light source by consuming 1 watt of energy is called Lamp efficiency.

Lamp efficiency = Total flux in Lumen / power consumption in watt

58. LED Lamp efficiency is 10  to 110 Lumen per watt.

59. Fluorescent Lamp efficiency is 50 to 100 Lumen per watt.

60. Incandescent Lamp efficiency is 4 to 17 Lumen per watt.

61. Sodium vapour Lamp efficiency is 100 to 200 Lumen per watt.

62. Incandescent and Halogen Lamp  maximum Colour Rendering Index ( CRI ) near  to 100. 

63. CRI is the ability of a light source to show true colour of an object near to natural as the object will look in day light. CRI count can be from zero to 100.

64. Highest level of illumination is required in proof reading.

65. Lowest level of illumination is found in railway platforms.

66. Insulators used for OHE are made up of porcelain ( Silicon 20% + Felspar 30% + clay 50%).

67. Metal graphite brushes are used for high value of current density in DC series motors.

68. Y, A, E, B, F, H and C are  classes of insulation and can withstand upto 90°C, 105 °C, 120°C, 130°C, 155°C, 180°C and greater than 180°C respectively.

69. C class insulation is used in transformers and Motors of Locomotives.

70. Silicon Carbide has maximum operating temperature range of 1600°C to 2500°C where as Nichrome has 1150°C.

71. Thermal conductivity of Nichrome is 11.3 W/mK.

72. Type 'B' MCB is used in houses, trips on 3 to 4 times load current in .04 to 13 milliseconds.

73. Type 'C' MCB is used in heavy loads like motors, trips on 5 to 10 times load current in .04 to 5 milliseconds.

74. Type 'D' MCB is used in Xray machine and welding machines, trips on 10 to 20 times load current in .4 to 3 milliseconds.

75. Type 'K' MCB is used in motors, Transformers in industrial applications, trips on 8 to 12 times load current in 0.1 milliseconds.

76. Type 'Z' MCB is used in semiconductor devices and electronic equipments, trips on 2 to 3 times load current in 0.1 milliseconds.

77. L series MCBs are used in resistive loads like Geysers, ovens etc.

78. G series MCB are used in inductive loads like Motors, Air Conditioners, Halogen Lamp etc.

79. DC series MCB is used in DC controls, Locomotives, Diesel Generator sets etc.

80. Fusing factor of protective devices for medium level load is 1.45 ( Kit Kat fuse).

81. Fusing factor for HRC fuse is 1.1 

82. Phenol plus formaldehyde forms Bakelite.

83. Buccholz relay is a gas actuated relay which is used for oil cooled transformer protection.

84. Capacitor start capacitor run induction motor is used in ceiling fan.

85. Multimeter is used to measure current,  voltage, resistance, Diode, transistor, and continuity of circuit.

86. Conductors have positive temperature coefficient of resistance.(i.e. on increasing temperature resistance also increases)

87. Insulator and semiconductor have negative temperature coefficient of resistance.

88. Megger is used to measure insulation resistance.

89. Megger is a combination of DC generator and  ohmmeter.

90. In ceiling fan paper capacitor of 2.3 microfarad is used to provide starting phase to make the fan self starting.

91. Electric press, Electric cattle works on heating effect.

92. In conventional Locomotives Air Circuit Breaker is used.

93. In ABB Locomotives Vaccum Circuit Breaker is used.

94. Electric spark temperature can be upto 2000°C that is why we use circuit Breaker for spark quenching and circuit breaking.

95. In electric bulbs tungsten wire is used.

96. In heaters Nichrome wire is used.

97. Universal motor is used in mixer and grinders.

98. Lead acid cell voltage is 2.1 to 2.25 volt and it is a secondary cell which is widely used in house hold Inverters.

99. Lithium Ion battery is used in mobile and laptops which provides 3.7 Volt voltage.

100. Nickel Cadmium cell is used in rechargeable cell which produces 1.2 to 1.45 volts of voltage.

This is enough for this article.

Stay tuned with us for electrical and Electronics knowledge.

Utmost care is  taken in writing the article if any error found please notify us, we will surely rectify it.

Thank You 

Author:- Amarjeet Singh Jamwal authored articles on Basic Electronics EngineeringElectric Traction, and Electronics Practical for INFO4EEE Website

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