02. Radiation
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Heat Transfer

149573 A blackbody is at a temperature of $2880 \mathrm{~K}$. The energy of radiation emitted by this body between $499 \mathrm{~nm}$ and $500 \mathrm{~nm}$ wavelengths is $U_{1}$, between $999 \mathrm{~nm}$ and $1000 \mathrm{~nm}$ is $U_{2}$ and between $1499 \mathrm{~nm}$ and $1500 \mathrm{~nm}$ is $U_{3}$. The Wien's constant $b=2.88 \times 10^{6} \mathrm{nmK}$. Then

1 $U_{1}$
2 $\mathrm{U}_{3}=0$
3 $\mathrm{U}_{1}>\mathrm{U}_{2}$
4 $\mathrm{U}_{2}>\mathrm{U}_{1}$
Assam CEE-2014
Heat Transfer

149574 Earth receives Sun's radiation at the rate of ' $P$ ' $\mathrm{Wm}^{-2}$. Mean distance between the Sun and the Earth is ' $r$ ' $m$. Radius of the Sun is ' $R$ ' $m$. If Stefan's constant is $\sigma$ (in SI units), surface temperature of the sun in Kelvin is

1 $\left|\frac{\mathrm{PR}^{2}}{\sigma \mathrm{r}^{2}}\right|^{\frac{1}{4}}$
2 $\left|\frac{\operatorname{Pr}}{\sigma \mathrm{R}}\right|^{\frac{1}{4}}$
3 $\left|\frac{\operatorname{Pr}^{2}}{\sigma \mathrm{R}^{2}}\right|^{\frac{1}{2}}$
4 $\left|\frac{\operatorname{Pr}^{2}}{\sigma \mathrm{R}^{2}}\right|^{\frac{1}{4}}$
AP EAMCET (Medical)-24.04.2019
Heat Transfer

149575 A steady current is passing through cylindrical conductor of radius ' $r$ ' placed in vacuum. Assuming Stefan's law of radiation, steady temperature will be proportional to

1 $\mathrm{r}^{-3}$
2 $\mathrm{r}^{-3 / 4}$
3 $\mathrm{r}^{-2 / 3}$
4 $\mathrm{r}^{-3 / 5}$
AP EAMCET-23.04.2019
Heat Transfer

149576 The intensity of direct sunlight before it enters the earth's atmosphere is $1.4 \mathrm{kWm}^{-2}$. If it is completely absorbed and completely reflected the corresponding radiation pressures are respectively

1 $2.35 \times 10^{-6} \mathrm{Nm}^{-2}, 4.7 \times 10^{-6} \mathrm{Nm}^{-2}$
2 $4.7 \times 10^{-6} \mathrm{Nm}^{-2}, 2.35 \times 10^{-6} \mathrm{Nm}^{-2}$
3 $9.3 \times 10^{-6} \mathrm{Nm}^{-2}, 4.7 \times 10^{-6} \mathrm{Nm}^{-2}$
4 $4.7 \times 10^{-6} \mathrm{Nm}^{-2}, 9.3 \times 10^{-6} \mathrm{Nm}^{-2}$
AP EAMCET-28.04.2017
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Heat Transfer

149573 A blackbody is at a temperature of $2880 \mathrm{~K}$. The energy of radiation emitted by this body between $499 \mathrm{~nm}$ and $500 \mathrm{~nm}$ wavelengths is $U_{1}$, between $999 \mathrm{~nm}$ and $1000 \mathrm{~nm}$ is $U_{2}$ and between $1499 \mathrm{~nm}$ and $1500 \mathrm{~nm}$ is $U_{3}$. The Wien's constant $b=2.88 \times 10^{6} \mathrm{nmK}$. Then

1 $U_{1}$
2 $\mathrm{U}_{3}=0$
3 $\mathrm{U}_{1}>\mathrm{U}_{2}$
4 $\mathrm{U}_{2}>\mathrm{U}_{1}$
Assam CEE-2014
Heat Transfer

149574 Earth receives Sun's radiation at the rate of ' $P$ ' $\mathrm{Wm}^{-2}$. Mean distance between the Sun and the Earth is ' $r$ ' $m$. Radius of the Sun is ' $R$ ' $m$. If Stefan's constant is $\sigma$ (in SI units), surface temperature of the sun in Kelvin is

1 $\left|\frac{\mathrm{PR}^{2}}{\sigma \mathrm{r}^{2}}\right|^{\frac{1}{4}}$
2 $\left|\frac{\operatorname{Pr}}{\sigma \mathrm{R}}\right|^{\frac{1}{4}}$
3 $\left|\frac{\operatorname{Pr}^{2}}{\sigma \mathrm{R}^{2}}\right|^{\frac{1}{2}}$
4 $\left|\frac{\operatorname{Pr}^{2}}{\sigma \mathrm{R}^{2}}\right|^{\frac{1}{4}}$
AP EAMCET (Medical)-24.04.2019
Heat Transfer

149575 A steady current is passing through cylindrical conductor of radius ' $r$ ' placed in vacuum. Assuming Stefan's law of radiation, steady temperature will be proportional to

1 $\mathrm{r}^{-3}$
2 $\mathrm{r}^{-3 / 4}$
3 $\mathrm{r}^{-2 / 3}$
4 $\mathrm{r}^{-3 / 5}$
AP EAMCET-23.04.2019
Heat Transfer

149576 The intensity of direct sunlight before it enters the earth's atmosphere is $1.4 \mathrm{kWm}^{-2}$. If it is completely absorbed and completely reflected the corresponding radiation pressures are respectively

1 $2.35 \times 10^{-6} \mathrm{Nm}^{-2}, 4.7 \times 10^{-6} \mathrm{Nm}^{-2}$
2 $4.7 \times 10^{-6} \mathrm{Nm}^{-2}, 2.35 \times 10^{-6} \mathrm{Nm}^{-2}$
3 $9.3 \times 10^{-6} \mathrm{Nm}^{-2}, 4.7 \times 10^{-6} \mathrm{Nm}^{-2}$
4 $4.7 \times 10^{-6} \mathrm{Nm}^{-2}, 9.3 \times 10^{-6} \mathrm{Nm}^{-2}$
AP EAMCET-28.04.2017
NEET DIGITAL LIBRARY
Heat Transfer

149573 A blackbody is at a temperature of $2880 \mathrm{~K}$. The energy of radiation emitted by this body between $499 \mathrm{~nm}$ and $500 \mathrm{~nm}$ wavelengths is $U_{1}$, between $999 \mathrm{~nm}$ and $1000 \mathrm{~nm}$ is $U_{2}$ and between $1499 \mathrm{~nm}$ and $1500 \mathrm{~nm}$ is $U_{3}$. The Wien's constant $b=2.88 \times 10^{6} \mathrm{nmK}$. Then

1 $U_{1}$
2 $\mathrm{U}_{3}=0$
3 $\mathrm{U}_{1}>\mathrm{U}_{2}$
4 $\mathrm{U}_{2}>\mathrm{U}_{1}$
Assam CEE-2014
Heat Transfer

149574 Earth receives Sun's radiation at the rate of ' $P$ ' $\mathrm{Wm}^{-2}$. Mean distance between the Sun and the Earth is ' $r$ ' $m$. Radius of the Sun is ' $R$ ' $m$. If Stefan's constant is $\sigma$ (in SI units), surface temperature of the sun in Kelvin is

1 $\left|\frac{\mathrm{PR}^{2}}{\sigma \mathrm{r}^{2}}\right|^{\frac{1}{4}}$
2 $\left|\frac{\operatorname{Pr}}{\sigma \mathrm{R}}\right|^{\frac{1}{4}}$
3 $\left|\frac{\operatorname{Pr}^{2}}{\sigma \mathrm{R}^{2}}\right|^{\frac{1}{2}}$
4 $\left|\frac{\operatorname{Pr}^{2}}{\sigma \mathrm{R}^{2}}\right|^{\frac{1}{4}}$
AP EAMCET (Medical)-24.04.2019
Heat Transfer

149575 A steady current is passing through cylindrical conductor of radius ' $r$ ' placed in vacuum. Assuming Stefan's law of radiation, steady temperature will be proportional to

1 $\mathrm{r}^{-3}$
2 $\mathrm{r}^{-3 / 4}$
3 $\mathrm{r}^{-2 / 3}$
4 $\mathrm{r}^{-3 / 5}$
AP EAMCET-23.04.2019
Heat Transfer

149576 The intensity of direct sunlight before it enters the earth's atmosphere is $1.4 \mathrm{kWm}^{-2}$. If it is completely absorbed and completely reflected the corresponding radiation pressures are respectively

1 $2.35 \times 10^{-6} \mathrm{Nm}^{-2}, 4.7 \times 10^{-6} \mathrm{Nm}^{-2}$
2 $4.7 \times 10^{-6} \mathrm{Nm}^{-2}, 2.35 \times 10^{-6} \mathrm{Nm}^{-2}$
3 $9.3 \times 10^{-6} \mathrm{Nm}^{-2}, 4.7 \times 10^{-6} \mathrm{Nm}^{-2}$
4 $4.7 \times 10^{-6} \mathrm{Nm}^{-2}, 9.3 \times 10^{-6} \mathrm{Nm}^{-2}$
AP EAMCET-28.04.2017
Join With Us for More Updates
Heat Transfer

149573 A blackbody is at a temperature of $2880 \mathrm{~K}$. The energy of radiation emitted by this body between $499 \mathrm{~nm}$ and $500 \mathrm{~nm}$ wavelengths is $U_{1}$, between $999 \mathrm{~nm}$ and $1000 \mathrm{~nm}$ is $U_{2}$ and between $1499 \mathrm{~nm}$ and $1500 \mathrm{~nm}$ is $U_{3}$. The Wien's constant $b=2.88 \times 10^{6} \mathrm{nmK}$. Then

1 $U_{1}$
2 $\mathrm{U}_{3}=0$
3 $\mathrm{U}_{1}>\mathrm{U}_{2}$
4 $\mathrm{U}_{2}>\mathrm{U}_{1}$
Assam CEE-2014
Heat Transfer

149574 Earth receives Sun's radiation at the rate of ' $P$ ' $\mathrm{Wm}^{-2}$. Mean distance between the Sun and the Earth is ' $r$ ' $m$. Radius of the Sun is ' $R$ ' $m$. If Stefan's constant is $\sigma$ (in SI units), surface temperature of the sun in Kelvin is

1 $\left|\frac{\mathrm{PR}^{2}}{\sigma \mathrm{r}^{2}}\right|^{\frac{1}{4}}$
2 $\left|\frac{\operatorname{Pr}}{\sigma \mathrm{R}}\right|^{\frac{1}{4}}$
3 $\left|\frac{\operatorname{Pr}^{2}}{\sigma \mathrm{R}^{2}}\right|^{\frac{1}{2}}$
4 $\left|\frac{\operatorname{Pr}^{2}}{\sigma \mathrm{R}^{2}}\right|^{\frac{1}{4}}$
AP EAMCET (Medical)-24.04.2019
Heat Transfer

149575 A steady current is passing through cylindrical conductor of radius ' $r$ ' placed in vacuum. Assuming Stefan's law of radiation, steady temperature will be proportional to

1 $\mathrm{r}^{-3}$
2 $\mathrm{r}^{-3 / 4}$
3 $\mathrm{r}^{-2 / 3}$
4 $\mathrm{r}^{-3 / 5}$
AP EAMCET-23.04.2019
Heat Transfer

149576 The intensity of direct sunlight before it enters the earth's atmosphere is $1.4 \mathrm{kWm}^{-2}$. If it is completely absorbed and completely reflected the corresponding radiation pressures are respectively

1 $2.35 \times 10^{-6} \mathrm{Nm}^{-2}, 4.7 \times 10^{-6} \mathrm{Nm}^{-2}$
2 $4.7 \times 10^{-6} \mathrm{Nm}^{-2}, 2.35 \times 10^{-6} \mathrm{Nm}^{-2}$
3 $9.3 \times 10^{-6} \mathrm{Nm}^{-2}, 4.7 \times 10^{-6} \mathrm{Nm}^{-2}$
4 $4.7 \times 10^{-6} \mathrm{Nm}^{-2}, 9.3 \times 10^{-6} \mathrm{Nm}^{-2}$
AP EAMCET-28.04.2017
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