document.write( "Question 715520: The resistance, R, of a wire varies directly as its length and inversely as the square of the diameter. The resistance of a wire 500ft long and diameter 0.01 in. is 20ohms. What is the resistance of a wire 1500ft long with diameter 0.02 in.? \n" ); document.write( "
Algebra.Com's Answer #439492 by DrBeeee(684)![]() ![]() ![]() You can put this solution on YOUR website! If the longer wire has the same diameter, its resistance would increase to \n" ); document.write( "(1) R = (1500/500)*20 or \n" ); document.write( "(2) R = 60 ohms \n" ); document.write( "However, it's diameter is twice as large, which means the resistance would decrease (a \"fatter\" wire has less resistance) by a factor of (d1/d2)^2 or \n" ); document.write( "(2) Rnew = ((.01/.02)^2)*60 or \n" ); document.write( "(3) Rnew = (1/4)*60 or \n" ); document.write( "(4) Rnew = 15 ohms \n" ); document.write( "Answer: The longer but larger diameter wire will have a resistance of 15 ohms. \n" ); document.write( " |