Answer
• Improving the environmental performances
• Developing Green Mining technology
Explanation
The effect to the environment caused by opal mining are; impact on soils and geology, clearing of native vegetation disrupting flora and fauna, change in land use and effects of air quality.
Opal mining is currently examining environmental impacts and adopting measures that mitigate the impacts making the process less destructive to the environment.
With the current commitment to sustainability, opal companies are investing funds for Green Mining as a positive way to impact the environment before and after mining.
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Answer: CaF2
Explanation:
Calcium is a metal and has 2+ cation charge. While F us in group 7 with an oxidation of -1.
So. Ca²+ F- do the criss cross rule where the charge of the cation will be the subscript of the anion and vice versa. So the result is CaF2
Answer:
50,000 V/m
Explanation:
The electric field between two charged metal plates is uniform.
The relationship between potential difference and electric field strength for a uniform field is given by the equation

where
is the potential difference
E is the magnitude of the electric field
d is the distance between the plates
In this problem, we have:
is the potential difference between the plates
d = 15 mm = 0.015 m is the distance between the plates
Therefore, rearranging the equation we find the strength of the electric field:

Answer:
the longest time needed to read an arbitrary sector located anywhere on the disk is 2971.24 ms
Explanation:
Given the data in the question;
first we determine the rotational latency
Rotational latency = 60/(3600×2) = 0.008333 s = 8.33 ms
To get the longest time, lets assume the sector will be found at the last track.
hence we will access all the track, meaning that 127 transitions will be done;
so the track changing time = 127 × 15 = 1905 ms
also, we will look for the sectors, for every track rotations that will be done;
128 × 8.33 = 1066.24 ms
∴The Total Time = 1066.24 ms + 1905 ms
Total Time = 2971.24 ms
Therefore, the longest time needed to read an arbitrary sector located anywhere on the disk is 2971.24 ms