Answer:

Explanation:
The electric flux through a certain surface is given by (for a uniform field):

where:
E is the magnitude of the electric field
A is the area of the surface
is the angle between the direction of the field and of the normal to the surface
In this problem, we have:
is the electric field
L = 2.0 m is the side of the sheet, so the area is

, since the electric field is perpendicular to the surface
Therefore, the electric flux is

First choice: the inability of current technology to capture
large amounts of the
Sun's energy
Well, it's true that large amounts of it get away ... our 'efficiency' at capturing it is still rather low. But the amount of free energy we're able to capture is still huge and significant, so this isn't really a major problem.
Second choice: the inability of current technology to store
captured solar
energy
No. We're pretty good at building batteries to store small amounts, or raising water to store large amounts. Storage could be better and cheaper than it is, but we can store huge amounts of captured solar energy right now, so this isn't a major problem either.
Third choice: inconsistencies in the availability of the resource
I think this is it. If we come to depend on solar energy, then we're
expectedly out of luck at night, and we may unexpectedly be out
of luck during long periods of overcast skies.
Fourth choice: lack of
demand for solar energy
If there is a lack of demand, it's purely a result of willful manipulation
of the market by those whose interests are hurt by solar energy.
Answer:
We feel cold when tap or well water in winter because heat flows from hot body to cold body.
Explanation:
Our <em>body</em><em> </em><em>is</em><em> </em><em>in</em><em> </em><em>optimal</em><em> </em><em>status</em><em> </em><em>is</em><em> </em><em>a</em><em> </em><em>hot</em><em> </em><em>body</em><em> </em><em>and</em><em> </em><em>tap</em><em> </em><em>or</em><em> </em><em>we</em><em>ll</em><em> </em><em>water</em><em> </em><em>is</em><em> </em><em>a</em><em> </em><em>cold</em><em> </em><em>body</em><em>.</em><em> </em><em>Theref</em><em>ore</em><em> </em><em>we</em><em> </em><em>feel</em><em> </em><em>cold</em><em>.</em>
The cube has 6 equal, square, foil faces. The mass of foil for each face is (380/6) milligrams.
The surface area of each piece is (380)/(6•11) cm^2.
The length of each side of the piece is √(380/6•11) cm
That's about 2.4 cm .
It's a cute little foil cube, just under 1-inch each way.