Q41. | The unit of luminous flux is | ||||||
A. | watt/m2 [Wrong Answer] |
B. | lumen [Correct Answer] |
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C. | lumen/m2 [Wrong Answer] |
D. | watt [Wrong Answer] |
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Q42. | The colour of sodium vapour discharge lamp is | ||||||
A. | red [Wrong Answer] |
B. | pink [Wrong Answer] |
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C. | yellow [Correct Answer] |
D. | bluish green [Wrong Answer] |
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Q43. | A reflector is provided to | ||||||
A. | protect the lamp [Wrong Answer] |
B. | provide better illumination [Wrong Answer] |
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C. | avoid glare [Wrong Answer] |
D. | do all of the above [Correct Answer] |
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Q44. | ____ does not have separate choke | ||||||
A. | Sodium vapour lamp [Correct Answer] |
B. | Fluorescent lamp [Wrong Answer] |
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C. | Mercury vapour lamp [Wrong Answer] |
D. | All of the above [Wrong Answer] |
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Q45. | A substance which change its electrical resistance when illuminated by light is called | ||||||
A. | photoelectric [Wrong Answer] |
B. | photovoltaic [Wrong Answer] |
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C. | phatoconductive [Correct Answer] |
D. | none of the above [Wrong Answer] |
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Q46. | Luminous flux is | ||||||
A. | the light energy radiated by sun [Wrong Answer] |
B. | the part of light energy, radiated by sun, which is received on the earth [Wrong Answer] |
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C. | the rate of energy radiation in the form of light waves [Correct Answer] |
D. | none of the above [Wrong Answer] |
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Q47. | Sky appears blue because of | ||||||
A. | refraction [Wrong Answer] |
B. | reflection [Wrong Answer] |
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C. | radiation [Wrong Answer] |
D. | scattering of light over dust particles [Correct Answer] |
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Q48. | The level of illumination on a surface least depends on | ||||||
A. | ambient temperature [Correct Answer] |
B. | candle power of the source [Wrong Answer] |
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C. | distance of the source [Wrong Answer] |
D. | type of reflector used [Wrong Answer] |
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Q49. | Filament lamps operate normally at a power factor of | ||||||
A. | 0.5 lagging [Wrong Answer] |
B. | 0.8 lagging [Wrong Answer] |
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C. | unity [Correct Answer] |
D. | 0.8 leading [Wrong Answer] |
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Q50. | Carbon arc lamps are commonly used in | ||||||
A. | photography [Wrong Answer] |
B. | cinema projectors [Correct Answer] |
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C. | domestic lighting [Wrong Answer] |
D. | street lighting [Wrong Answer] |
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