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question_answer1)
On a clear sunny day, an object at temperature T is placed on the top of a high mountain. An identical object at the same temperature is placed at the foot of mountain. If both the objects are exposed to sun-rays for two hours in an identical manner, the object at the top of the mountain will register a temperature [CPMT 1988]
A)
Higher than the object at the foot done
clear
B)
Lower than the object at the foot done
clear
C)
Equal to the object at the foot done
clear
D)
None of the above done
clear
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question_answer2)
The velocity of heat radiation in vacuum is [EAMCET 1982; KCET 1998]
A)
Equal to that of light done
clear
B)
Less than that of light done
clear
C)
Greater than that of light done
clear
D)
Equal to that of sound done
clear
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question_answer3)
In which process, the rate of transfer of heat is maximum [EAMCET 1977; MP PMT 1994; MH CET 2001]
A)
Conduction done
clear
B)
Convection done
clear
C)
Radiation done
clear
D)
In all these, heat is transferred with the same velocity done
clear
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question_answer4)
Which of the following is the correct device for the detection of thermal radiation [Manipal MEE 1995, UPSEAT 2000]
A)
Constant volume thermometer done
clear
B)
Liquid-in-glass thermometer done
clear
C)
Six's maximum and minimum thermometer done
clear
D)
Thermopile done
clear
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question_answer5)
A thermos flask is polished well [AFMC 1996]
A)
To make attractive done
clear
B)
For shining done
clear
C)
To absorb all radiations from outside done
clear
D)
To reflect all radiations from outside done
clear
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question_answer6)
Heat travels through vacuum by [AIIMS 1998; CPMT 2003]
A)
Conduction done
clear
B)
Convection done
clear
C)
Radiation done
clear
D)
Both (a) and (b) done
clear
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question_answer7)
The energy supply being cut-off, an electric heater element cools down to the temperature of its surroundings, but it will not cool further because [CPMT 2001]
A)
Supply is cut off done
clear
B)
It is made of metal done
clear
C)
Surroundings are radiating done
clear
D)
Element & surroundings have same temp. done
clear
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question_answer8)
We consider the radiation emitted by the human body. Which of the following statements is true [CBSE PMT 2003]
A)
The radiation is emitted only during the day done
clear
B)
The radiation is emitted during the summers and absorbed during the winters done
clear
C)
The radiation emitted lies in the ultraviolet region and hence is not visible done
clear
D)
The radiation emitted is in the infra-red region done
clear
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question_answer9)
The earth radiates in the infra-red region of the spectrum. The spectrum is correctly given by [RPET 2002; AIEEE 2003]
A)
Wien?s law done
clear
B)
Rayleigh jeans law done
clear
C)
Planck?s law of radiation done
clear
D)
Stefan?s law of radiation done
clear
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question_answer10)
Infrared radiation is detected by [AIEEE 2002]
A)
Spectrometer done
clear
B)
Pyrometer done
clear
C)
Nanometer done
clear
D)
Photometer done
clear
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question_answer11)
Pick out the statement which is not true [KCET 2002]
A)
IR radiations are used for long distance photography done
clear
B)
IR radiations arise due to inner electron transitions in atoms done
clear
C)
IR radiations are detected by using a bolometer done
clear
D)
Sun is the natural source of IR radiation done
clear
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question_answer12)
A hot and a cold body are kept in vacuum separated from each other. Which of the following cause decrease in temperature of the hot body [AFMC 2005]
A)
Radiation done
clear
B)
Convection done
clear
C)
Conduction done
clear
D)
Temperature remains unchanged done
clear
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question_answer13)
Good absorbers of heat are [J & K CET 2002]
A)
Poor emitters done
clear
B)
Non-emitters done
clear
C)
Good emitters done
clear
D)
Highly polished done
clear
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question_answer14)
For a perfectly black body, its absorptive power is [MP PMT 1989, 92; RPMT 2001; RPET 2001, 03; AFMC 2003]
A)
1 done
clear
B)
0.5 done
clear
C)
0 done
clear
D)
Infinity done
clear
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question_answer15)
Certain substance emits only the wavelengths \[{{\lambda }_{1}},\ {{\lambda }_{2}},\ {{\lambda }_{3}}\] and \[{{\lambda }_{4}}\] when it is at a high temperature. When this substance is at a colder temperature, it will absorb only the following wavelengths [MP PET 1990]
A)
\[{{\lambda }_{1}}\] done
clear
B)
\[{{\lambda }_{2}}\] done
clear
C)
\[{{\lambda }_{1}}\] and \[{{\lambda }_{2}}\] done
clear
D)
\[{{\lambda }_{1}},\ {{\lambda }_{2}},\ {{\lambda }_{3}}\] and \[{{\lambda }_{4}}\] done
clear
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question_answer16)
As compared to the person with white skin, the person with black skin will experience [CPMT 1988]
A)
Less heat and more cold done
clear
B)
More heat and more cold done
clear
C)
More heat and less cold done
clear
D)
Less heat and less cold done
clear
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question_answer17)
Relation between emissivity \[e\] and absorptive power \[a\] is (for black body)
A)
\[e=a\] done
clear
B)
\[e=\frac{1}{a}\] done
clear
C)
\[e={{a}^{2}}\] done
clear
D)
\[a={{e}^{2}}\] done
clear
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question_answer18)
Which of the following statements is wrong [BCECE 2001]
A)
Rough surfaces are better radiators than smooth surface done
clear
B)
Highly polished mirror like surfaces are very good radiators done
clear
C)
Black surfaces are better absorbers than white ones done
clear
D)
Black surfaces are better radiators than white done
clear
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question_answer19)
Half part of ice block is covered with black cloth and rest half is covered with white cloth and then it is kept in sunlight. After some time clothes are removed to see the melted ice. Which of the following statements is correct
A)
Ice covered with white cloth will melt more done
clear
B)
Ice covered with black cloth will melt more done
clear
C)
Equal ice will melt under both clothes done
clear
D)
It will depend on the temperature of surroundings of ice done
clear
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question_answer20)
If between wavelength \[\lambda \]and \[\lambda +d\lambda \], \[{{e}_{\lambda }}\]and \[{{a}_{\lambda }}\] be the emissive and absorptive powers of a body and \[{{E}_{\lambda }}\] be the emissive power of a perfectly black body, then according to Kirchoff's law, which is true [RPMT 1998; MP PET 1991]
A)
\[{{e}_{\lambda }}={{a}_{\lambda }}={{E}_{\lambda }}\] done
clear
B)
\[{{e}_{\lambda }}{{E}_{\lambda }}={{a}_{\lambda }}\] done
clear
C)
\[{{e}_{\lambda }}={{a}_{\lambda }}{{E}_{\lambda }}\] done
clear
D)
\[{{e}_{\lambda }}{{a}_{\lambda }}{{E}_{\lambda }}\]= constant done
clear
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question_answer21)
When \[p\]calories of heat is given to a body, it absorbs \[q\] calories; then the absorbtion power of body will be
A)
\[p/q\] done
clear
B)
\[q/p\] done
clear
C)
\[{{p}^{2}}/{{q}^{2}}\] done
clear
D)
\[{{q}^{2}}/{{p}^{2}}\] done
clear
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question_answer22)
Distribution of energy in the spectrum of a black body can be correctly represented by [MP PMT 1989]
A)
Wien's law done
clear
B)
Stefan's law done
clear
C)
Planck's law done
clear
D)
Kirchhoff's law done
clear
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question_answer23)
In rainy season, on a clear night the black seat of a bicycle becomes wet because
A)
It absorbs water vapour done
clear
B)
Black seat is good absorber of heat done
clear
C)
Black seat is good radiator of heat energy done
clear
D)
None of the above done
clear
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question_answer24)
There is a rough black spot on a polished metallic plate. It is heated upto 1400 K approximately and then at once taken in a dark room. Which of the following statements is true [NCERT 1984; CPMT 1998]
A)
In comparison with the plate, the spot will shine more done
clear
B)
In camparison with the plate, the spot will appear more black done
clear
C)
The spot and the plate will be equally bright done
clear
D)
The plate and the black spot can not be seen in the dark room done
clear
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question_answer25)
At a certain temperature for given wave length, the ratio of emissive power of a body to emissive power of black body in same circumstances is known as [RPMT 1997]
A)
Relative emissivity done
clear
B)
Emissivity done
clear
C)
Absorption coefficient done
clear
D)
Coefficient of reflection done
clear
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question_answer26)
The cause of Fraunhoffer lines is [RPMT 1996; EAMCET 2001]
A)
Reflection of radiations by chromosphere done
clear
B)
Absorption of radiations by chromosphere done
clear
C)
Emission of radiations by chromosphere done
clear
D)
Transmission of radiations by chromosphere done
clear
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question_answer27)
Two thermometers A and B are exposed in sun light. The valve of A is painted black, But that of B is not painted. The correct statement regarding this case is [BHU (Med.) 1999; MH CET 1999]
A)
Temperature of A will rise faster than B but the final temperature will be the same in both done
clear
B)
Both A and B show equal rise in beginning done
clear
C)
Temperature of A will remain more than B done
clear
D)
Temperature of B will rise faster done
clear
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question_answer28)
There is a black spot on a body. If the body is heated and carried in dark room then it glows more. This can be explained on the basis of [RPET 2000]
A)
Newton?s law of cooling done
clear
B)
Wien?s law done
clear
C)
Kirchoff?s law done
clear
D)
Stefan?s done
clear
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question_answer29)
When red glass is heated in dark room it will seem [RPET 2000]
A)
Green done
clear
B)
Purple done
clear
C)
Black done
clear
D)
Yellow done
clear
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question_answer30)
A hot body will radiate heat most rapidly if its surface is [UPSEAT 1999, 2000]
A)
White & polished done
clear
B)
White & rough done
clear
C)
Black & polished done
clear
D)
Black & rough done
clear
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question_answer31)
A body, which emits radiations of all possible wavelengths, is known as [CPMT 2001; Pb. PET 2002]
A)
Good conductor done
clear
B)
Partial radiator done
clear
C)
Absorber of photons done
clear
D)
Perfectly black-body done
clear
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question_answer32)
Which of the following is the example of ideal black body [AIEEE 2002; CBSE PMT 2002]
A)
Kajal done
clear
B)
Black board done
clear
C)
A pin hole in a box done
clear
D)
None of these done
clear
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question_answer33)
An ideal black body at room temperature is thrown into a furnace. It is observed that [IIT-JEE (Screening) 2002]
A)
Initially it is the darkest body and at later times the brightest done
clear
B)
It is the darkest body at all times done
clear
C)
It cannot be distinguished at all times done
clear
D)
Initially it is the darkest body and at later times it cannot be distinguished done
clear
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question_answer34)
Absorption co-efficient of an open window is... [KCET 2004]
A)
Zero done
clear
B)
0.5 done
clear
C)
1 done
clear
D)
0.25 done
clear
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question_answer35)
Which of the prism is used to see infra-red spectrum of light [RPMT 2000]
A)
Rock-salt done
clear
B)
Nicol done
clear
C)
Flint done
clear
D)
Crown done
clear
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question_answer36)
Which of the following statement is correct [RPMT 2001]
A)
A good absorber is a bad emitter done
clear
B)
Everybody absorbs and emits radiations at every temperature done
clear
C)
The energy of radiations emitted from a black body is same for all wavelengths done
clear
D)
The law showing the relation of temperatures with the wavelength of maximum emission from an ideal black body is Plank?s law done
clear
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question_answer37)
A piece of blue glass heated to a high temperature and a piece of red glass at room temperature, are taken inside a dimly lit room then [KCET 2005]
A)
The blue piece will look blue and red will look as usual done
clear
B)
Red look brighter red and blue look ordinary blue done
clear
C)
Blue shines like brighter red compared to the red piece done
clear
D)
Both the pieces will look equally red. done
clear
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question_answer38)
Which of the following law states that ?good absorbers of heat are good emitters? [Orissa JEE 2005]
A)
Stefan?s law done
clear
B)
Kirchoff?s law done
clear
C)
Planck?s law done
clear
D)
Wein?s law done
clear
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