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Following graphs show the variation in the intensity of heat radiations by the black body and frequency at a fixed temperature. Choose the correct option.

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Important Questions on Heat Transfer

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Physics>Heat and Thermodynamics>Heat Transfer>Wien’s Displacement Law
The wavelength of the radiation emitted by a black body is 6 mm and Wein's constant is 3×10-3 mK. Then temperature of black body is
EASY
Physics>Heat and Thermodynamics>Heat Transfer>Wien’s Displacement Law
In the case of black body for energy distribution, energy radiated by a blackbody which is given by, Planck's formula reduces to Rayleigh Jean's formula for
MEDIUM
Physics>Heat and Thermodynamics>Heat Transfer>Wien’s Displacement Law
The power radiated by a black body is P and it radiates maximum energy at wavelength, λ0. If the temperature of the black body is now changed so that it radiates maximum energy at wavelength 34λ0, the power radiated by it becomes nP. The value of n is
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Physics>Heat and Thermodynamics>Heat Transfer>Wien’s Displacement Law

The plots of intensity versus wavelength for three black bodies at temperature T1, T2, T3, respectively, are shown in the figure. Their temperatures are such that

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Physics>Heat and Thermodynamics>Heat Transfer>Wien’s Displacement Law
A black body has maximum wavelength λm at temperature 2200 K. Its corresponding wavelength at temperature 3300 K will be
MEDIUM
Physics>Heat and Thermodynamics>Heat Transfer>Wien’s Displacement Law
Three stars A, B, C have surface temperatures TA, TB,TC  respectively. Star A appears bluish, star B appears reddish and star C yellowish. Hence,
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Physics>Heat and Thermodynamics>Heat Transfer>Wien’s Displacement Law
Ordinary bodies A and B radiate maximum energy with wavelength difference 4 μm. The absolute temperature of body A is 3 times that of B. The wavelength at which body B radiates maximum energy is
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Physics>Heat and Thermodynamics>Heat Transfer>Wien’s Displacement Law
On observing light from three different stars P , Q and R , it was found that intensity of violet colour is maximum in the spectrum of P , the intensity of green colour is maximum in the spectrum of R and the intensity of red colour is maximum in the spectrum of Q . If Tp, TQ and TR are the respective absolute temperatures of P , Q and R , then it can be concluded from the above observations that :
HARD
Physics>Heat and Thermodynamics>Heat Transfer>Wien’s Displacement Law
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 wavelength of 350 nm. If these stars behave like black bodies, then the ratio of surface temperatures of the sun and north star is
MEDIUM
Physics>Heat and Thermodynamics>Heat Transfer>Wien’s Displacement Law
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 blackbodies, then the ratio of the surface temperature of the sun and the north star is
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Physics>Heat and Thermodynamics>Heat Transfer>Wien’s Displacement Law
A black body at 200 K is found to emit maximum energy at a wavelength of 14μm. When its temperature is raised to 1000 K, the wavelength at which maximum energy is emitted is
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Physics>Heat and Thermodynamics>Heat Transfer>Wien’s Displacement Law

The maximum energy in thermal radiation from a source occurs at the wavelength 4000Å. The effective temperature of the source is b =2.93×10-3

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Physics>Heat and Thermodynamics>Heat Transfer>Wien’s Displacement Law
The plots for intensity versus wavelength for three black bodies at temperature T1, T2, T3 respectively are shown in figure. Their temperatures are such that
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EASY
Physics>Heat and Thermodynamics>Heat Transfer>Wien’s Displacement Law
Two stars radiate maximum energy at wavelengths 3.6 × 10-5 cm and 4.8 × 10-5 cm respectively. What is the ratio of their temperatures?
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Physics>Heat and Thermodynamics>Heat Transfer>Wien’s Displacement Law
The plots of intensity of radiation versus wavelength of three black bodies at temperatures T1, T2 and T3 are shown. Then,

Question Image
EASY
Physics>Heat and Thermodynamics>Heat Transfer>Wien’s Displacement Law
Following graphs show the variation in the intensity of heat radiations by the black body and frequency at a fixed temperature. Choose the correct option.
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Physics>Heat and Thermodynamics>Heat Transfer>Wien’s Displacement Law
The wavelength corresponding to the maximum energy, released during an atomic explosion was 2.93×10-10 m. Given that the wien's constant is b=2.93×10-3 m K, then the maximum temperature attained must be of the order of
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Physics>Heat and Thermodynamics>Heat Transfer>Wien’s Displacement Law
The wavelength λm=5.5×10-7 m when temperature of sun is 5500 K. If the furnace has wavelength λm equal to 11×10-7 m, then temperature of furnace is
MEDIUM
Physics>Heat and Thermodynamics>Heat Transfer>Wien’s Displacement Law
The plots of intensity versus wavelength for three black bodies at temperatures T1, T2 and T3 respectively are as shown. Their temperatures are such that

Question Image
EASY
Physics>Heat and Thermodynamics>Heat Transfer>Wien’s Displacement Law
On observing light from three different stars P,Q and R, it was found that intensity of violet colour is maximum in the spectrum of P, the intensity of green colour is maximum in the spectrum of R and the intensity of red colour is maximum in the spectrum of Q. If Tp, TQ and TR are the respective absolute temperatures of P, Q and R, then it can be concluded from the above observations that :