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question_answer1)
According to Wein's law [DCE 1995, 96; MP PET/PMT 1988 DPMT 1999; AIIMS 2002; CBSE PMT 2004]
A)
\[{{\lambda }_{m}}T\]= constant done
clear
B)
\[\frac{{{\lambda }_{m}}}{T}\]= constant done
clear
C)
\[\frac{T}{{{\lambda }_{m}}}\]= constant done
clear
D)
\[T+{{\lambda }_{m}}\]= constant done
clear
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question_answer2)
On investigation of light from 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 observations it can be concluded that [CPMT 1989]
A)
The temperature of A is maximum, B is minimum and C is intermediate done
clear
B)
The temperature of A is maximum, C is minimum and B is intermediate done
clear
C)
The temperature of B is maximum, A is minimum and C is intermediate done
clear
D)
The temperature of C is maximum, B is minimum and A is intermediate done
clear
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question_answer3)
If wavelengths of maximum intensity of radiations emitted by the sun and the moon are \[0.5\times {{10}^{-6}}m\] and \[{{10}^{-4}}m\] respectively, the ratio of their temperatures is [MP PMT 1990]
A)
1/100 done
clear
B)
1/200 done
clear
C)
100 done
clear
D)
200 done
clear
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question_answer4)
The wavelength of radiation emitted by a body depends upon [MP PMT 1992]
A)
The nature of its surface done
clear
B)
The area of its surface done
clear
C)
The temperature of its surface done
clear
D)
All the above factors done
clear
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question_answer5)
If black wire of platinum is heated, then its colour first appear red, then yellow and finally white. It can be understood on the basis of [MP PMT 1984]
A)
Wien's displacement law done
clear
B)
Prevost theory of heat exchange done
clear
C)
Newton's law of cooling done
clear
D)
None of the above done
clear
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question_answer6)
Colour of shining bright star is an indication of its [AIIMS 2001; RPMT 1999; BCECE 2005]
A)
Distance from the earth done
clear
B)
Size done
clear
C)
Temperature done
clear
D)
Mass done
clear
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question_answer7)
The wavelength of maximum emitted energy of a body at 700 K is 4.08 \[\mu m\]. If the temperature of the body is raised to 1400 K, the wavelength of maximum emitted energy will be [MP PET 1990]
A)
\[1.02\ \mu m\] done
clear
B)
16.32\[\mu m\] done
clear
C)
8.16\[\mu m\] done
clear
D)
2.04\[\mu m\] done
clear
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question_answer8)
A black body at 200 K is found to exit maximum energy at a wavelength of \[14\mu m\]. When its temperature is raised to 1000K, the wavelength at which maximum energy is emitted is [RPMT 1998; MP PET 1991; BVP 2003]
A)
\[14\mu m\] done
clear
B)
\[70\mu F\] done
clear
C)
\[2.8\mu m\] done
clear
D)
\[2.8mm\] done
clear
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question_answer9)
Two stars emit maximum radiation at wavelength 3600\[{AA}\] and 4800\[{AA}\] respectively. The ratio of their temperatures is [MP PMT 1991]
A)
1 : 2 done
clear
B)
3 : 4 done
clear
C)
4 : 3 done
clear
D)
2 : 1 done
clear
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question_answer10)
A black body emits radiations of maximum intensity at a wavelength of \[5000{AA}\], when the temperature of the body is \[{{1227}^{o}}C\]. If the temperature of the body is increased by \[{{1000}^{o}}C\], the maximum intensity of emitted radiation would be observed at [MP PET 1992]
A)
\[2754.8{AA}\] done
clear
B)
\[3000{AA}\] done
clear
C)
\[3500{AA}\] done
clear
D)
\[4000{AA}\] done
clear
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question_answer11)
Four pieces of iron heated in a furnace to different temperatures show different colours listed below. Which one has the highest temperature [MP PET 1992]
A)
White done
clear
B)
Yellow done
clear
C)
Orange done
clear
D)
Red done
clear
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question_answer12)
If a black body is heated at a high temperature, it seems to be [DPMT 2001]
A)
Blue done
clear
B)
White done
clear
C)
Red done
clear
D)
Black done
clear
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question_answer13)
If the temperature of the sun becomes twice its present temperature, then [MP PET 1989; RPMT 1996]
A)
Radiated energy would be predominantly in infrared done
clear
B)
Radiated energy would be predominantly in ultraviolet done
clear
C)
Radiated energy would be predominantly in X-ray region done
clear
D)
Radiated energy would become twice the present radiated energy done
clear
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question_answer14)
The maximum energy in the thermal radiation from a hot source occurs at a wavelength of \[11\times {{10}^{-5}}cm\]. According to Wein's law, the temperature of the source (on Kelvin scale) will be \[n\] times the temperature of another source (on Kelvin scale) for which the wavelength at maximum energy is \[5.5\times {{10}^{-5}}cm\]. The value \[n\] is [CPMT 1991]
A)
2 done
clear
B)
4 done
clear
C)
\[\frac{1}{2}\] done
clear
D)
1 done
clear
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question_answer15)
The wavelength of maximum energy released during an atomic explosion was \[2.93\times {{10}^{-10}}m\]. Given that Wein's constant is \[2.93\times {{10}^{-3}}m-K\], the maximum temperature attained must be of the order of [Haryana CEE 1996; MH CET 2002; Pb. PET 2000]
A)
\[{{10}^{-7}}K\] done
clear
B)
\[{{10}^{7}}K\] done
clear
C)
\[{{10}^{-13}}K\] done
clear
D)
\[5.86\times {{10}^{7}}K\] done
clear
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question_answer16)
The maximum wavelength of radiation emitted at \[2000\ K\]is \[4\mu m\]. What will be the maximum wavelength of radiation emitted at [MP PMT/PET 1998; DPMT 2000]
A)
\[3.33\ \mu m\] done
clear
B)
\[0.66\ \mu m\] done
clear
C)
\[1\ \mu m\] done
clear
D)
\[1\ m\] done
clear
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question_answer17)
How is the temperature of stars determined by [BHU 1999, 02; DCE 2000, 03]
A)
Stefan?s law done
clear
B)
Wein?s displacement law done
clear
C)
Kirchhoff?s law done
clear
D)
Ohm?s law done
clear
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question_answer18)
On increasing the temperature of a substance gradually, which of the following colours will be noticed by you [Pb. PMT 1995; Pb. PET 1996; CPMT 1995, 98; KCET 2000]
A)
White done
clear
B)
Yellow done
clear
C)
Green done
clear
D)
Red done
clear
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question_answer19)
A black body has maximum wavelength \[{{\lambda }_{m}}\] at temperature 2000 K. Its corresponding wavelength at temperature 3000 K will be [CBSE PMT 2001; Kerala PET 2005]
A)
\[\frac{3}{2}{{\lambda }_{m}}\] done
clear
B)
\[\frac{2}{3}{{\lambda }_{m}}\] done
clear
C)
\[\frac{4}{9}{{\lambda }_{m}}\] done
clear
D)
\[\frac{9}{4}{{\lambda }_{m}}\] done
clear
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question_answer20)
Relation between the colour and the temperature of a star is given by [Kerala PET 2001]
A)
Wein?s displacement law done
clear
B)
Planck?s law done
clear
C)
Hubble?s law done
clear
D)
Fraunhofer diffraction law done
clear
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question_answer21)
A black body at a temperature of 1640 K has the wavelength corresponding to maximum emission equal to 1.75\[\mu \]. Assuming the moon to be a perfectly black body, the temperature of the moon, if the wavelength corresponding to maximum emission is 14.35 m is [Kerala (Med.) 2002]
A)
100 K done
clear
B)
150 K done
clear
C)
200 K done
clear
D)
250 K done
clear
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question_answer22)
The maximum wavelength of radiations emitted at 900 K is \[4\mu m\]. What will be the maximum wavelength of radiations emitted at 1200 K [BHU 2002]
A)
\[3\mu m\] done
clear
B)
\[0.3\mu m\] done
clear
C)
\[1\mu m\] done
clear
D)
\[1\,\,m\] done
clear
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question_answer23)
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 4800Å. If the sun were to cool down from 6000 K to 3000 K then the peak intensity would occur at a wavelength [UPSEAT 2002]
A)
4800Å done
clear
B)
9600Å done
clear
C)
7200Å done
clear
D)
6400Å done
clear
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question_answer24)
What will be the ratio of temperatures of sun and moon if the wavelengths of their maximum emission radiations rates are 140 Å and 4200 Å respectively [J & K CET 2004]
A)
1 : 30 done
clear
B)
30 : 1 done
clear
C)
42 : 14 done
clear
D)
14 : 42 done
clear
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question_answer25)
The radiation energy density per unit wavelength at a temperature T has a maximum at a wavelength l0. At temperature \[2T\], it will have a maximum at a wavelength [UPSEAT 2004]
A)
4l0 done
clear
B)
2l0 done
clear
C)
l0/2 done
clear
D)
l0/4 done
clear
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question_answer26)
The absolute temperatures of two black bodies are 2000 K and 3000 K respectively. The ratio of wavelengths corresponding to maximum emission of radiation by them will be [RPMT 2003]
A)
2 : 3 done
clear
B)
3 : 2 done
clear
C)
9 : 4 done
clear
D)
4 : 9 done
clear
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question_answer27)
The temperature of sun is 5500 K and it emits maximum intensity radiation in the yellow region \[(5.5\times {{10}^{-7}}m)\]. The maximum radiation from a furnace occurs at wavelength \[11\times {{10}^{-7}}m.\]The temperature of furnace is [J & K CET 2000]
A)
1125 K done
clear
B)
2750 K done
clear
C)
5500 K done
clear
D)
11000 K done
clear
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question_answer28)
A particular star (assuming it as a black body) has a surface temperature of about \[5\times {{10}^{4}}K.\]The wavelength in nanometers at which its radiation becomes maximum is (b = 0.0029 mK) [EAMCET (Med.) 2003]
A)
48 done
clear
B)
58 done
clear
C)
60 done
clear
D)
70 done
clear
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question_answer29)
The maximum energy in thermal radiation from a source occurs at the wavelength 4000Å. The effective temperature of the source is [AMU (Engg.) 1999]
A)
\[7325\,K\] done
clear
B)
\[80000K\] done
clear
C)
\[{{10}^{4}}\,K\] done
clear
D)
\[{{10}^{6}}\,K\] done
clear
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question_answer30)
The intensity of radiation emitted by the sun has its maximum value at a wavelength of \[510\ nm\] and that emitted by the north star has the maximum value at \[350\ nm\]. If these stars behave like black bodies, then the ratio of the surface temperature of the sun and north star is [IIT 1997 Cancelled; JIPMER 2000; AIIMS 2000]
A)
1.46 done
clear
B)
0.69 done
clear
C)
1.21 done
clear
D)
0.83 done
clear
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