document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=62972>Question 62972</A>: <I><SPAN STYLE=\"word-break: break-all;\"> a wire of length 20 m and diameter 0.6 cmTHE ELECTRICAL RESISTANCE r OF A WIRE VARIES DIRECTLY AS ITS LENGTH l AND INVERSELY AS THE SQUARE OF ITS DIAMETER.  A WIRE 20 METERS LONG AND 0.6 CENTIMETERS IN DIAMETER MADE FROM A CERTAIN ALLOY HAS A RESISTANCE OF 36 OHMS.  WHAT IS THE RESISTANCE OF A PIECE OF WIRE 60 METERS LONG AND 1.2 CENTIMETERS IN DIAMETER MADE FROM THE SAME MATERIAL?   </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #43806 by </B><A HREF=/tutors/aboutme.mpl?userid=uma><B>uma(370)</B></A><img src=\"/images/stars/stars-10.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=uma><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=43806\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Let K be the constant of proportionality.\r<BR>\n" );
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document.write( "Then r = K*l/(d^2) wher d is the diameter.\r<BR>\n" );
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document.write( "Given that a wire of length 20 m and diameter 0.6 cm has a resistance of 36 ohms\r<BR>\n" );
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document.write( "==> 36 = K* 2000/((0.6)^2)\r<BR>\n" );
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document.write( "==> 36 = K*2000/(0.36)\r<BR>\n" );
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document.write( "Multiplying both the sides by 0.36/2000 we get,\r<BR>\n" );
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document.write( "36*(0.36/2000) = K\r<BR>\n" );
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document.write( "==> 0.00648 = K\r<BR>\n" );
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document.write( "Now the equation for resistance becomes,\r<BR>\n" );
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document.write( "r = 0.00648*l/(d^2) \r<BR>\n" );
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document.write( "When l = 6000cm and d = 1.2 cm\r<BR>\n" );
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document.write( "r = 0.00648 *(6000/(1.2)^2\r<BR>\n" );
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document.write( "==> r = 0.00648 * (6000/1.44)\r<BR>\n" );
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document.write( "==> r = 27\r<BR>\n" );
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document.write( "Thus the resistance of 20 m long wire with diameter 1.2cm is 27 ohms.\r<BR>\n" );
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document.write( "Good Luck!!! </SPAN>\n" );
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