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    Hello, I'm stuck on these questions

    Q1) What length of copper wire of diameter 0.38mm would be need to limit the current in it to 0.5A when connected to a 2V battery?

    A=\pi (0.19 \times10^{-3})^2

    A=1.13 \times 10^{-7}

    V=IR

    2=0.5R

    R=4

    R=\frac{pL}{A}

    4=\frac{1.7\times10^{-8}\times L}{1.13\times 10^{-7}}

    \frac{4(1.13 \times10^{-7})}{1.7 \times10^{-8}}=L, L=26.7

    Is that correct?

    Q2)A 0.28mm diameter copper wire, 15.0m long, is connected to a 3.0V battery. Find its resistance and the current flowing.

    A=\pi(0.14 \times10^{-3})^2

    A=6.18 \times 10^{-8}

    ...What do I do next to answer the question?

    Thanks a lot.
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    Duplicate question already answered in the other thread.
 
 
 
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Updated: September 28, 2010
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