Answer:
D. Cooler
Explanation:
The Sun's surface has a temperature ranging from 6 000 Kelvin, thus it is very hot. The radioactive reaction in the core of the Sun is a nuclear fusion reaction. This reaction ensures continuous release of high energy from the surface of the Sun.
But during the reaction, some parts becomes cooler than other parts on its surface. Which is due to the release of high amount of energy into space. The Sun's spot can be found in the cooler part of the Sun.
Answer:
50% of it .
Explanation:
50% of it is illuminated by the Sun.
First body:

Second body:

From description of the task we have:
Volumetric cylinders and volumetric flasks
Answer:
The air fraction to be removed is 0.11
Given:
Initial temperature, T =
= 283 K
Pressure, P = 250 kPa
Finally its temperature increases, T' =
= 318 K
Solution:
Using the ideal gas equation:
PV = mRT
where
P = Pressure
V = Volume
m = no. of moles of gas
R = Rydberg's Constant
T = Temperature
Now,
Considering the eqn at constant volume and pressure, we get:
mT = m'T'
Thus
(1)
Now, the fraction of the air to be removed for the maintenance of pressure at 250 kPa:

From eqn (1):

