MIME-Version: 1.0 Content-Location: file:///C:/D9286902/Summer08.Phys1112.Quiz5.SolutionWeb.htm Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset="us-ascii" Department of Natural Sciences

 

Clayton State University

Department = of Natural Sciences

 

June 12, 2008=

Physics 111= 2 – Quiz 5

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Name  __SOLUTION___________________________________

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10.0 m length of a copper wire (r =3D 1.77 x 10-8 W-m, a =3D 3.8 x 10-3 (oC)-1, at 20oC) with a diameter of 2= .05 mm carries a current of 15.0 at 20o C.

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  1. What is the resistance of= the wire?

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R =3D r L/A

 

R =3D r L/(p R2) =3D&= nbsp; (1.77 x 10-8 W-m) (10.0 m)/(p (0.001025 m)2)  =3D  0.053= 6  W

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  1. What is the potential difference across the ends of the wire?

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DV =3D I R =3D (15.0 A)(0.0536  W)  =3D  0.804 V

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  1. What is the resistance of= the wire as the temperature increases to 300oC?

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= R =3D R0 [1 + a (T-T0)]=

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= R =3D (0.0536 W) [1 + (3.8 x 10-3 (oC)-1) (300oC - 20oC)] =3D 0.111 W=

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