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question_answer1)
It is hotter for the same distance over the top of a fire than it is in the side of it, mainly because [NCERT 1976, 79, 80; AIIMS 2000]
A)
Air conducts heat upwards done
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B)
Heat is radiated upwards done
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C)
Convection takes more heat upwards done
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D)
Convection, conduction and radiation all contribute significantly transferring heat upwards done
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question_answer2)
One likes to sit under sunshine in winter season, because
A)
The air surrounding the body is hot by which body gets heat done
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B)
We get energy by sun done
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C)
We get heat by conduction by sun done
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D)
None of the above done
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question_answer3)
Air is bad conductor of heat or partly conducts heat, still vacuum is to be placed between the walls of the thermos flask because
A)
It is difficult to fill the air between the walls of thermos flask done
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B)
Due to more pressure of air, the thermos can get crack done
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C)
By convection, heat can flow through air done
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D)
On filling the air, there is no advantage done
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question_answer4)
While measuring the thermal conductivity of a liquid, we keep the upper part hot and lower part cool, so that [CPMT 1985; MP PMT/PET 1988]
A)
Convection may be stopped done
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B)
Radiation may be stopped done
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C)
Heat conduction is easier downwards done
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D)
It is easier and more convenient to do so done
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question_answer5)
For proper ventilation of building, windows must be open near the bottom and top of the walls so as to let pass
A)
In more air done
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B)
In cool air near the bottom and hot air out near the roof done
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C)
In hot air near the roof and cool air out near the bottom done
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D)
Out hot air near the roof done
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question_answer6)
The layers of atmosphere are heated through [MP PET 1986]
A)
Convection done
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B)
Conduction done
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C)
Radiation done
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D)
(b) and (c) both done
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question_answer7)
Mode of transmission of heat, in which heat is carried by the moving particles, is [KCET 1999]
A)
Radiation done
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B)
Conduction done
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C)
Convection done
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D)
Wave motion done
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question_answer8)
In a closed room, heat transfer takes place by [BHU 2001]
A)
Conduction done
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B)
Convection done
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C)
Radiation done
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D)
All of these done
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question_answer9)
In heat transfer, which method is based on gravitation [CBSE PMT 2000]
A)
Natural convection done
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B)
Conduction done
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C)
Radiation done
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D)
Stirring of liquids done
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question_answer10)
When fluids are heated from the bottom, convection currents are produced because [UPSEAT 2000]
A)
Molecular motion of fluid becomes aligned done
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B)
Molecular collisions take place within the fluid done
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C)
Heated fluid becomes more dense than the cold fluid above it done
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D)
Heated fluid becomes less dense than the cold fluid above it done
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question_answer11)
If a liquid is heated in weightlessness, the heat is transmitted through [RPMT1996]
A)
Conduction done
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B)
Convection done
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C)
Radiation done
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D)
Neither, because the liquid cannot be heated in weightlessness done
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question_answer12)
The rate of loss of heat from a body cooling under conditions of forced convection is proportional to its heat capacity surface area absolute temperature excess of temperature over that of surrounding : state if [NCERT 1982]
A)
A, B, C are correct done
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B)
Only A and C are correct done
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C)
Only B and D are correct done
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D)
Only D is correct done
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question_answer13)
In which of the following process, convection does not take place primarily [IIT-JEE (Screening) 2005]
A)
Sea and land breeze done
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B)
Boiling of water done
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C)
Warming of glass of bulb due to filament done
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D)
Heating air around a furnace done
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