Question

4. The electrical resistance of a wire varies inversely as the square of its radius. If the resistance is 0.80 ohm when the radius is 0.4cm. Find the resistance whom the radius is 0.7cm.​

Answer 1

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Answer:

0.261 ohm

Explanation:

If the radius increases by a factor of 0.7/0.4= 7/4, the square of this factor is (7/4)^2 = 49/16. The inverse of this square is 16/49, which is the factor by which the resistance changed.

The resistance of the larger wire is ...

(16/49)(0.80 ohm) ≈ 0.261 ohm