Wien's Displacement Law

Q.

Two bodies A and B have thermal emissivities of 0.01 and 0.81 respectively. The outer surface areas of the two bodies are the same . The two bodies emit total radiant power at the same rate. The wavelength ${\lambda }_B$ corresponding to maximum spectral radiancy in the radiation from B shifted from the wavelength corresponding to maximum spectral radiancy in the radiation from A, by 1.00 $\mu m$. If the temperature of A is 5802 K

1. the temperature of B is 1934 K

2. ${\lambda }_B=1.5\mu m$

3. the temperature of B is 11604 K

4. the temperature of B is 2901 K

Q. The power radiated by a black body is P and it radiates maximum energy at wavelength, ${\lambda }_0$. If the temperature of the black body is now changed so that it radiates maximum energy at wavelength $\frac{3}{4}{\lambda }_0$, the power radiated by it becomes nP. The value of n is?

1. $\frac{256}{81}$
2. $\frac{3}{4}$
3. $\frac{81}{256}$
4. $\frac{4}{3}$

Q. If at temperature $T_1=1000K$, the wavelength is $1.4\times {10}^{-6}m$, then at what temperature the wavelength will be $2.8\times {10}^{-6}m$

1. 500 K
2. 250 K
3. None of these
4. 2000 K

Q.

Experimental investigations show that the intensity of the solar radiation is maximum for a wavelength $4750\hat{A}$ in the visible region. If the surface temperature of the sun is 6000 K, what is the value of the Wien’s constant b?

1. 

2. 

3. 

4. 

Q. The Wien’s displacement law express relation between

1. Frequency and temperature
2. Temperature and amplitude
3. Wavelength and radiating power of black body
4. Wavelength corresponding to maximum energy and temperature

Q.

Experimental investigations show that the intensity of solar radiation is maximum for a wavelength $480nm$ in the visible region. Estimate the surface temperature of the sun. Given Wien's constant, $b=2.88\times {10}^{-3}mK$.

1. ${10}^{6}K$

2. 5000 K

3. 6000 K

4. 8000 K

Q. If the temperature of a black body increases from ${17}^{\circ }C$ to ${307}^{\circ }C$, then the rate of energy radiation will become:-

1. $4$ times
2. $16$ times
3. $32$ times
4. $8$ times

Q. Wein's constant is $2892\times {10}^{-6}$ MKS unit and the value of ${\lambda }_m$ from moon is 14.46 microns. What is the surface temperature of moon

1. 100 K
2. 300 K
3. 400 K
4. 200 K

Q.

The energy spectrum of a blackbody exhibits a maximum around a wavelength ${\lambda }_0$. The temperature of the black body is now changed such that the energy is maximum around a wavelength $\frac{3{\lambda }_0}{4}$ The power radiated by the blackbody will now increase by a factor:

1. None

2. 256/81

3. 16/9

4. 4/3

Q. A black body at a high temperature $T$ radiates energy at the rate of $U\left(inW/m^2\right)$. When the temperature falls to half (i.e $T/2$), the radiated energy $\left(inW/m^2\right)$ will be

1. $U/16$
2. $U/4$
3. $U/8$
4. $U/2$

Q.

Two bodies A and B have thermal emissivities of 0.01 and 0.81 respectively. The outer surface areas of the two bodies are the same . The two bodies emit total radiant power at the same rate. The wavelength ${\lambda }_B$ corresponding to maximum spectral radiancy in the radiation from B shifted from the wavelength corresponding to maximum spectral radiancy in the radiation from A, by 1.00 $\mu m$. If the temperature of A is 5802 K

1. the temperature of B is 1934 K

2. ${\lambda }_B=1.5\mu m$

3. the temperature of B is 11604 K

4. the temperature of B is 2901 K

Q.

Variation of radiant energy emitted by sun, filament of tungsten lamp and welding arc as a function of its wavelength is shown in figure. Which of the following option is the correct match? (IIT JEE 2005)

1. Sun - T₃, tungsten filament - T₁, welding are - T₂

2. Sun - T₁, tungsten filament - T₂, welding are - T₃

3. Sun - T₃, tungsten filament - T₂, welding are - T₁

4. Sun - T₂, tungsten filament - T₁, welding are - T₃