85. Electrostatic precipitator is used to control the pollution of?
86. Tungsten is used for the manufacture of the filament of an electric bulb, because?
A.It is a good conductor
B.It is economical
C.It is malleable
D.It has a very high melting point
87. What is the wavelength of visible spectrum?
A.1300 g-3000 A?
B.3900 A? - 7600 A?
C.7800 A? - 8000 A?
D.8500 - 9800 A?
88. Who measured the velocity of light first?
89. When a vehicle passes, TV reception gets distorted. This is because?
A.Metal reflects radio waves
B.spark plug creates electromagnetic disturbances
C.vehicle pollution affects the performance of the 'IV components
D.modern vehicles use electro ignition system
90. The energy emitted by the Sun is due to?
D.All of the above
91. The sky appears blue because of?
A.Atmospheric water vapour
B.Scattering of light
C.Reflection on sea water
D.Emission of blue wavelength by the sun
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