1) 
The capacitance of a parallel-plate capacitor is given by:

where
is the vacuum permittivity
A is the area of each plate
d is the distance between the plates
Here, the radius of each plate is

so the area is

While the separation between the plates is

So the capacitance is

And now we can find the energy stored,which is given by:

2) 0.71 J/m^3
The magnitude of the electric field is given by

and the energy density of the electric field is given by

and using
, we find

Answer: The green house effect is best described by option 4 (Energy given off by earth is reflected off of earth's atmosphere back down to the surface).
Explanation:
The green house effect can be described as the energy given off by earth is reflected off of earth's atmosphere back down to the surface.
When energy from the sun passes through the atmosphere, some are absorbed which keeps the earth surface warm. While the rest is reflected back largely by cloud.
The energy which is emitted from the earth surface is called the infrared radiation. Some of the infrared radiation passess through the atmosphere but most is absorbed and re- emitted in all directions by the greenhouse gas molecules and clouds. This effect warms the earth surface and the lower atmosphere. Therefore this statement (Energy given off by earth is reflected off of earth's atmosphere back down to the surface) is correct about greenhouse effect.
For the greenhouse effect to occur, greenhouse gas molecules are mostly needed. Examples of these gases include:
--> Carbon dioxide (CO2),
--> Water vapor (H2O), and
--> Methane (CH4)
Over the years, the excessive human activities has lead to increase in the greenhouse gas molecules which has negatively affected the greenhouse effects.
Answer:
Recall that Earth’s radius is 6.38 × 106 m and Earth’s mass is 5.97 × 1024 kg.
Explanation:
Number of miles that marker shows when passes through town= 160 miles.
Number of miles that marker shows currently to John = 115 miles.
We need to find the distance between town and John's current location.
For the problem, we can clearly see that Town is at 160 miles away but when John passes the marker shows 115 miles.
So, it's just the difference between 160 miles and 115 miles.
In order to find that difference, we need to subtract those two numbers.
160miles - 115miles = 45 miles.
So, we could say the distance between town and John's current location is 45 miles.
Answer:
The answer is C 1.8V and 0.38A