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    Copper wire length, iron wire resistance, cost of hall light

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    Resistivity Problems:

    1. How long should a copper wire 0.4mm in diameter be for it to have a resistance of 10ohms? The resistivity of copper is 1.7 x 10-8 Q-m
    Answer: 74m

    2. An iron wire has a resistance of 0.20ohms at 20°C and a resistance of 0.30ohms at 110°C. Find the temperature coefficient of resistance of the iron used in the wire.
    Answer: 0.0056/°C

    Electrical Power Problems:
    1. A 75-W hall light is left on continuously. At $0.09 per kilowatt-hour, find the cost per week.
    Answer: $1.13

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    https://brainmass.com/physics/power/copper-wire-length-iron-wire-resistance-cost-hall-light-303254

    Solution Preview

    Resistivity Problems:

    1. How long should a copper wire 0.4mm in diameter be for it to have a resistance of 10ohms? The resistivity of copper is 1.7 x 10-8 Q-m

    Answer: 74m

    Solution:

    The resistance and resistivity are related by the following equation:
    ρ=R A/l
    where  is the resistivity in  m,
    R is the resistance in ,
    A is the cross-sectional area in ...

    Solution Summary

    The expert examines the copper wire length, iron wire resistance and the cost of hall light.

    $2.19