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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

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.

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

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

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