Answer:
a) R = ρ₀ L /π(r_b² - R_a²)
, b) ρ₀ = V / I π (r_b² - R_a²) / L
Explanation:
a) The resistance of a material is given by
R = ρ l / A
where ρ is the resistivity, l is the length and A is the area
the length is l = L and the resistivity is ρ = ρ₀
the area is the area of the cylindrical shell
A = π r_b² - π r_a²
A = π (r_b² - r_a²)
we substitute
R = ρ₀ L /π(r_b² - R_a²)
b) The potential difference is related to current and resistance by ohm's law
V = i R
we subsist the expression of resistance
V = I ρ₀ L /π (r_b² - R_a²)
ρ₀ = V / I π (r_b² - R_a²) / L
Answer:
7.5 cm
Explanation:
In the figure we can see a sketch of the problem. We know that at the bottom of the U-shaped tube the pressure is equal in both branches. Defining 
Ethyl alcohol density and 
Glycerin density , we can write:
Simplifying:
On the other hand:
Rearranging:
Replacing (2) in (1):
Rearranging:
Data:
I think it is because the electrons repel each other
id have to say its thunder
