<h2>
Answer:</h2>
1.68 x 10⁻⁸Ωm
<h2>
Explanation:</h2>
The resistance (R) of a wire is related to its length(L), its material resistivity(ρ) and its crossectional area(A) as follows;
R = ρL/A ------------------------(i)
Where;
A = πd² / 4 [where d = diameter of the wire]
From the question;
L = 6.90m
d = 2.15mm = 0.00215m
R = 0.0320Ω
First calculate the crossectional area (A) of the wire as follows;
A = πd² / 4
[Take π = 3.142]
d = 0.00215m
∴ A = 3.142 x (0.00215)² / 4
∴ A = 0.000003631m²
Now, substitute the values of A, L, and R into equation (i) as follows;
R = ρL/A
0.0320 = ρ x 6.90 / 0.000003631
0.0320 = 1900302.95 x ρ
Solve for ρ;
=> ρ = 0.0320 / 1900302.95
=> ρ = 1.68 x 10⁻⁸Ωm
Therefore, the resistivity of the material of the wire is 1.68 x 10⁻⁸Ωm
Answer;
B. Increased levels of carbon dioxide, a greenhouse gas, leads to increased phytoplankton growth.
Explanation;
-A combination of warm water, high nutrient levels, and adequate sunlight may cause a harmful algae bloom. These blooms may damage aquatic ecosystems by blocking sunlight and depleting oxygen that other organisms need to survive.
-Algae blooms have been increasing globally, and climate change may be playing a role in the increment. For instance, during the warm summer season or when water is warmer, some harmful types of algae to grow faster than other, more benign varieties.
-Additionally, the warmer surface water also prevents water from mixing vertically, allowing algae to grow thicker and faster.
This is false. they flow west to east
Answer:
Exposure time limitation, shielding and distance.
Explanation:
- Limitation of exposure time, since the dose received is directly proportional to the exposure time, so that, at a shorter time, lower dose. For this reason, planning is suggested, to reduce time.
-
Use of shields. This allows a reduction in the dose received by the technician when filtered by the barrier (screen). There are two types of shields or screens, the primary barriers (attenuate the radiation of the primary beam) and the secondary barriers (avoid diffuse radiation).
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Distance to the radioactive source. The dose received is inversely proportional to the square of the distance to the radioactive source. Therefore, if the distance is doubled, the dose received will decrease by a quarter. Reason for this, it is advisable to use devices or remote controls whenever possible.
