1
AIEEE 2006
+4
-1
Assuming the Sun to be a spherical body of radius $$R$$ at a temperature of $$TK$$, evaluate the total radiant powered incident of Earth at a distance $$r$$ from the Sun

Where r0 is the radius of the Earth and $$\sigma$$ is Stefan's constant.

A
$$4\pi r_0^2{R^2}\sigma {{{T^4}} \over {{r^2}}}$$
B
$$\pi r_0^2{R^2}\sigma {{{T^4}} \over {{r^2}}}$$
C
$$r_0^2{R^2}\sigma {{{T^4}} \over {4\pi {r^2}}}$$
D
$${R^2}\sigma {{{T^4}} \over {{r^2}}}$$
2
AIEEE 2006
+4
-1
Two rigid boxes containing different ideal gases are placed on a table. Box A contains one mole of nitrogen at temperature $${T_0},$$ while Box contains one mole of helium at temperature $$\left( {{7 \over 3}} \right){T_0}.$$ The boxes are then put into thermal contact with each other, and heat flows between them until the gases reach a common final temperature (ignore the heat capacity of boxes). Then, the final temperature of the gases, $${T_f}$$ in terms of $${T_0}$$ is
A
$${T_f} = {3 \over 7}{T_0}$$
B
$${T_f} = {7 \over 3}{T_0}$$
C
$${T_f} = {3 \over 2}{T_0}$$
D
$${T_f} = {5 \over 2}{T_0}$$
3
AIEEE 2005
+4
-1
A gaseous mixture consists of $$16$$ $$g$$ of helium and $$16$$ $$g$$ of oxygen. The ratio $${{Cp} \over {{C_v}}}$$ of the mixture is
A
$$1.62$$
B
$$1.59$$
C
$$1.54$$
D
$$1.4$$
4
AIEEE 2005
+4
-1
A system goes from $$A$$ to $$B$$ via two processes $$I$$ and $$II$$ as shown in figure. If $$\Delta {U_1}$$ and $$\Delta {U_2}$$ are the changes in internal energies in the processes $$I$$ and $$II$$ respectively, then
A
relation between $$\Delta {U_1}$$ and $$\Delta {U_2}$$ can not be determined
B
$$\Delta {U_1} = \Delta {U_2}$$
C
$$\Delta {U_2} < \Delta {U_1}$$
D
$$\Delta {U_2} > \Delta {U_1}$$
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