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
It's a physical change. the water is changing it's physical state
The magnitude of the electric field will be the greatest at the point where it is closest,to its charges.
Yes ,there is a point where the field will be zero.
what is an electric field?
The region where an electrostatic force is experienced by a charged entity is known as the electric field at a point.
As per the principle of field lines and vectors,where the field lines are in a close manner together,the field will be strongest.However ,where the field lines are in a manner apart,the field will be the weakest.
As per the concept,the electric field will be the greatest at the point where it is closest to its charges.For like charges, the electric field will be zero closer to the smaller charge and will be along the line joining the two charges. For opposite charges of equal magnitude, there will not be any zero electric fields.
Thus,we can conclude that there will be a point where the electric field is zero
learn more about electric field from here: brainly.com/question/28197462
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Answer:
Athlete A
Explanation:
Power is the rate of doing work and it is calculated as follows:
Power = work done/time taken = mgh/t
(for work being done against gravity)
So for athlete A
P = (100 kg * 9.8 N/kg* 0.6m)/0.5 s = 1176 W
For athlete B
P = (150 kg * 9.8 N/kg* 0.6m)/1 s = 882 W
For athlete C
P = (200 kg * 9.8 N/kg* 0.6m)/2 s = 588 W
For athlete D
P = (250 kg * 9.8 N/kg* 0.6m)/2.5 s = 588
