Explanation:
4.
Resistance is proportional to length divided by the area, so if all dimensions are doubled, the resistance is multiplied by ...
2/2² = 1/2
The resistance is halved.
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5.
A coulomb is the amount of charge conveyed by a current of 1 ampere in 1 second, so the time will be ...
(6.5 C)/(3.5 A) = (6.5/3.5) A·s/A ≈ 1.857 s
The closest choice is 1.8 s.
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6.
The non-conductor, glass, will have the highest resistivity.
