The text does not specify whether the resistance R of the wire must be kept the same or not: here I assume R must be kept the same.
The relationship between the resistance and the resistivity of a wire is
where
is the resistivity
A is the cross-sectional area
R is the resistance
L is the wire length
the cross-sectional area is given by
where r is the radius of the wire. Substituting in the previous equation ,we find
For the new wire, the length L is kept the same (L'=L) while the radius is doubled (r'=2r), so the new resistivity is
Therefore, the new resistivity must be 4 times the original one.
<span>Nuclear energy is cleaner while generating electricity. Nuclear fission provides energy without releasing greenhouse gases such as carbon dioxide. However, nuclear power plants generate significant amounts of radioactive waste. That is why we should not choose nuclear energy over fossil fuel power plants.</span>
Answer:
Ф_cube /Ф_sphere = 3 /π
Explanation:
The electrical flow is
Ф = E A
where E is the electric field and A is the surface area
Let's shut down the electric field with Gauss's law
Фi = ∫ E .dA = 
/ ε₀
the Gaussian surface is a sphere so its area is
A = 4 π r²
the charge inside is
q_{int} = Q
we substitute
E 4π r² = Q /ε₀
E = 1 / 4πε₀ Q / r²
To calculate the flow on the two surfaces
* Sphere
Ф = E A
Ф = 1 / 4πε₀ Q / r² (4π r²)
Ф_sphere = Q /ε₀
* Cube
Let's find the side value of the cube inscribed inside the sphere.
In this case the radius of the sphere is half the diagonal of the cube
r = d / 2
We look for the diagonal with the Pythagorean theorem
d² = L² + L² = 2 L²
d = √2 L
we substitute
r = √2 / 2 L
r = L / √2
L = √2 r
now we can calculate the area of the cube that has 6 faces
A = 6 L²
A = 6 (√2 r)²
A = 12 r²
the flow is
Ф = E A
Ф = 1 / 4πε₀ Q/r² (12r²)
Ф_cubo = 3 /πε₀ Q
the relationship of these two flows is
Ф_cube /Ф_sphere = 3 /π
Answer:
The territory of Scotland was divided into two parts -- the highlands and the lowlands.
Explanation:
The people living in places of high altitudes are called highlanders. These high altitude places are called high lands and places with low elevations or altitudes are called the low lands. There are many differences between the two places and people experiences different difficulties in these places.
Some of the differences are :
The life of the people living in high lands are much more tougher than those living in the low lands. The highlanders have to work more hard than lowlanders.
The agricultural activities are more flourished in the low lands than in the high lands.
The low lands are more populated and highly industrialized than the high lands. Iron and steel industry, metal working industry and agriculture are some of the main industries of lowlands. They are the land of the Scottish nation.
Answer: Energy
Explanation: The ability to do work or cause change is called energy. Energy comes from many sources, and is found in two main forms. One form, potential energy, is energy that has the potential, in an object at rest, to do work later. An example of this would be a car parked at the top of a hill with its brakes on.
