JEE Questions for Physics Thermal Properties Of Matter Quiz 13 - MCQExams.com

The velocity of heat radiation in vaccum is
  • Equal to that of light
  • Less than that of light
  • Greater than that of light
  • Equal to that of sound
In which process, the rate of transfer of heat is maximum
  • Conduction
  • Convection
  • Radiation
  • In all these, heat is transferred with the same velocity
Which of the following is the correct device for the detection of thermal radiation
  • Constant volume thermometer
  • Liquid-in-glass thermometer
  • Six's maximum and minimum thermometer
  • Thermopile
A thermos flask is polished well
  • To make attractive
  • For shining
  • To absorb all radiations from outside
  • To reflect all radiations from outside
Which of the following law states that \'\'good absorbers of heat are good emitters\ ?
  • Stefan's law
  • Kirchoff's law
  • Planck's law
  • Weins'law
The earth radiates in the infra-red region of the spectrum is correctly given by
  • Wien's law
  • Rayleigh jeans law
  • Planck's law of radiation
  • Stefan's law of radiation
Infrared radiation is detected by
  • Spectrometer
  • pyrometer
  • nanometer
  • Phrotometer
Pick out the statement which is not true?
  • IR radiations are used for long distance photography
  • IR radiations arise due to inner electron transitions in atome
  • IR radiations are detected by using a bolometer
  • Sun is the natural source of IR radiation
Good absorbers of heat are
  • Poor emitters
  • Non-emitters
  • Good emitters
  • Highly polished
Certain substances emits only the wavelength λ1, λ2, λ3 and λ4 when it is at a high temperature. When this substance is at a colder temperature, it will absorb only the following wavelengths
  • λ1
  • λ2
  • λ1 and λ2
  • λ1, λ2, λ3 and λ4
As compared to the person with white skin, the person with black skin will experience
  • Less heat and more cold
  • More heat and more cold
  • More heat and less cold
  • Less heat and less cold
A red flower kept in green light will appear
  • Red
  • Yellow
  • Black
  • White
Which of the following statements is wrong?
  • Rough surfaces are better radiators than smooth surface
  • Highly polished mirror like surfaces are very good radiators
  • Black surfaces are better absorbers than white ones
  • Black surfaces are better radiators than white
If between wavelength λ and λ + dλ, eλ and aλ be the emissive and absorptive powers of a body and Eλ be the emissive power of a perfectly black body, then according to Kirchoff\'s law which is true
  • eλ = aλ = Eλ
  • eλEλ = aλ
  • eλ = aλEλ
  • eλaλEλ = constant
Distribution of energy in the spectrum of a black body can be correctly represented by
  • Wein's law
  • Stefan's law
  • Planck's law
  • Kirchhoff's law
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
  • The blue piece will look blue and red will look as usual
  • Red look brighter red and blue look oridinary blue
  • Blue shines like brighter red compared to the red piece
  • Both he pieces will look equally red
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?
  • In comparison with the plate, the spot will shine more
  • In comparision with the plate, the spot will appear more black
  • The spot and the plate will be equally bright
  • The plate and the black spot can not be seen in the dark room
Two thermometer 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
  • Temperature of A will rise faster than B but the final temperature will be the same in both
  • Both A and B show equal rise in beginning
  • Temperature of A will remain more than B
  • Temperature of B will rise faster
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
  • Newton's law of cooling
  • Wien's law
  • Kirchhoff's law
  • Stefan's law
A hot body will radiate heat most rapidly if its surface is
  • Whit and polished
  • White and rough
  • Black and polished
  • Black and rough
An ideal black body at room temperature is thrown into a furnace. It s observed that
  • Initially it is the darkest body and at later times the brightest
  • It is the darkest body at all times
  • It cannot be distinguished at all times
  • Initially it is the darkest bosy and at later times it cannot be distinguished
Absorption coefficient of an open window is
  • Zero
  • 0.5
  • 1
  • 0.25
According to Wien\'s alw

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On investigation of light fro three different stars A, B and C. It was found that in the spectrum of A the intensity of red colour is maximum, in B the intensity of blue colour is maximum and in C the intensity of yellow colour is maximum. From these observation it can be concluded that
  • The temperature of A is maximum, B is minimum and C is intermediate
  • The temperature of A is maximum, C is minimum and B is intermediate
  • The temperature of B is maximum, A is minimum and C is intermediate
  • The temperature of C is maximum, B is minimum and A is intermeidate
If wavelength of maximum intensity of radiations emitted by the sun and the moon are 0.5 × 10–1 m and 10–4m respectively, the ratio of their temperature is
  • 1/100
  • 1/200
  • 100
  • 200
The wavelength of radiation emitted by a body depends upon
  • The nature of its surface
  • The area of its surface
  • The temperature of its surface
  • All the above factors
If black wire of platinum o heated, then its colour first appear red, then yellow and family white. It can be understood on basis of
  • Wein's displacement
  • Prevost theory of heat exchange
  • Newton's law of cooling
  • None of the above
Four pieces of iron heated in a furnace to different temperatures show different colours listed below. Which one has the highest temperature?
  • White
  • Yellow
  • Orange
  • Red
The wavelength of maximum energy released during an atomic explosion was 2.93 × 10–10 m. Given that Wien\'s constant is 2.93 × 10–3 m-K, the maximum temperature attained must be of order of
  • 10–7 K
  • 107 K
  • 10–13 K
  • 5.86 × 10–7 K
The temperature of stars is determined by
  • Stefan's law
  • Wien's displacement law
  • Kirchhoff's law
  • Ohm's law
On increasing the temperature of a substance gradually, which of the following colours will be noticed by you?
  • White
  • Yellow
  • Green
  • Red
Relation between the colour and temperature of a star is given by
  • Wien's displacement law
  • Planck's law
  • Hubble's law
  • Fraunhoffer diffraction law
The maximum energy in thermal radiation from a source occurs at the wavelength 4000 Å. The effective temperature of the source is
  • 7000 K
  • 80000 K
  • 104 K
  • 106 K
Solar radiation emitted by sun resembles that emitted by a black body at a temperature of 6000 K. Maximum intensity is emitted at a wavelength of about 4800 Å. If the sun were to cool down from 6000 K to 3000 K, then the peak intensity would occur at a wavelength
  • 4800 Å
  • 9600Å
  • 7200 Å
  • 6400 Å
The radiation energy density per unit wavelength at a temperature T has a maximum at a wavelength λ0. At temperature 2T, it will have a maximum at a wavelength
  • 4λ0
  • 2λ0
  • λ0/2
  • λ0/4
The temperature of sun is 5500 K and it emits maximum intensity radiation in the yellow region (5.5 × 10–7 m). The maximum radiation from a furnace occurs at wavelength 11 × 10–7 m. The temperature of furnace is
  • 1125 K
  • 2750 K
  • 5500 K
  • 11000 K
The surface temperature of the sun is
  • 2900 K
  • 4000 K
  • 5800 K
  • 9000 K
A metal ball of surface area 200 cm2 and temperature 527oC is surrounded by a vessel at 27oC. If the emissivity of the metal is 0.4, then the rate of loss of heat from the ball is (σ = 5.67 × 10–8 J/m2–s–K4)
  • 108 J approx
  • 168 J approx
  • 182 J aprox
  • 192 J approx
The temperature of a piece of iron is 27oC and it is radiating energy at the rate of Q kWm–2. If its temperature is raised to 151oC, the rate of radiation of energy will become approximately
  • 2 Q kWm–2
  • 4 Q kWm–2
  • 6 Q kWm–2
  • 8 Q kWm–2
The temperature of two bodies A and B are 727oC and 127oC. The ratio of rate of emission of radiations will be
  • 727/127
  • 625/16
  • 1000/400
  • 100/16
The temperature at which a black body of unit area loses its energy at the rate of 1 joule/second is
  • –65oC
  • 65oC
  • 65 K
  • None of these
The tungsten filament of an electric lamp has a surface area A and a power rating P. If the emissivity of the filament is ϵ and σ is Stefan\'s constant, the steady temperature of the filament will be

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A thin square steel plate with each side equal to 10 cm is heated by a blacksmith. The rate of radiates energy by the heated plate is 1134 W. The temperature of the hot steel plate is (Stefan\'s constant σ = 5.67 × 10–8 watt m–2K–4, emissivity of the plate = 1)
  • 1000 k
  • 1189 K
  • 2000 K
  • 2378 K
The energy emitted per second by a black body at 27oC is 10 J. If the temperature of the black is increased to 327oC, the energy emitted per second will be
  • 20 J
  • 40 J
  • 80 J
  • 160 J
A spherical black body with a radius of 12 cm radiates 440 W power at 500 K. If the radius were halved and the temperatures doubled, the power radiated in watt would be
  • 225
  • 450
  • 900
  • 1800
The rectangular surface of area 8 cm × 4 cm of a black body at a temperature of 127oC emits energy at the rate of E per second. If the length and breadth of the surface are each reduced to half of the initial value and the temperature is raised to 327oC, the rate of emission of energy will become

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At temperature T, the power radiated by a body is Q watts. At the temperature 3T the power radiated by it will be
  • 3 Q
  • 9 Q
  • 27 Q
  • 81 Q
Two spherical black of radii r1 and r2 and with surface temperature T1 and T2 respectively radiate the same power. Then, the ratio of r1 and r2 will be

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Temperature of a black body increases from 327oC to 927oC, the initial energy possessed is 2 KJ, what is its final energy?
  • 32 KJ
  • 320 KJ
  • 1200 KJ
  • None of these
The original temperature of a black body is 727oC. The temperature at which this black body must be raised so as to double the total radiant energy is
  • 971 K
  • 1190 K
  • 2001 K
  • 1458 K
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