| 1. | In larger industrial and commercial reciprocating compression systems, refrigerent widely used is ? | |
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ammonia
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carbon dioxide
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sulphur dioxide
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R-12
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Report Question| 2. | Kirchhoff's law states that ? | |
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the total radiation from a black body per second per unit area is directly proportional to the fourth power of the absolute temperature
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the wave length corresponding to the maximum energy is proportional to the absolute temperature
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the ratio of the emissive power and absorptive power of all bodies is the same and is equal to the emissive power of a perfectly black body
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none of the above
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| 3. | The process of heat transfer from one particle of the body to another by the actual motion of the heated particles, is called ? | |
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conduction
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convection
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heating
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radiation
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| 4. | Conduction is a process of heat transfer ? | |
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from one particle of the body to another without the actual motion of the particles
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from one particle of the body to another by the actual motion of the heated particles
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from a hot body to a cold body, in a straight line, without affecting the intervening medium
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none of the above
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| 5. | The refrigerant widely used in domestic refrigerators is ? | |
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ammonia
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carbon dioxide
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sulphur dioxide
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R-12
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| 6. | Environmental protection agencies advice against the use of chloro-fluoro-carbon refrigerants since ? | |
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these react with water vapour and cause acid rain
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these react with plants and cause green-house effect
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these react with oxygen and cause its depletion
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these react with ozone layer
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| 7. | The operating pressure for refrigerating units using R-12 as a refrigerant is ? | |
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2 bar
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8 bar
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15 bar
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30 bar
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| 8. | R-12 is generally preferred over R-22 in deep freezers since ? | |
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it has low operating pressures
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it gives higher coefficient of performance
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it is miscible with oil over large range of temperatures
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all of the above
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| 9. | Most air cooled condensers are designed to operate with a temperature difference of ? | |
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5°C
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8°C
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14°C
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22°C
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| 10. | The natural convection air cooled condensers are used in ? | |
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domestic refrigerators
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water coolers
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room air conditioners
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all of these
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