document.write( "Question 1156584: The electrical resistance r of a wire varies directly with its length l and inversely with the square of its diameter d. 100 m of wire with diameter 3 mm has resistance of 8 ohms. What is the resistance of 150 m of wire with diameter of 4 mm? \n" ); document.write( "

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The electrical resistance r of a wire varies directly with its length l and inversely with the square of its diameter d. 100 m of wire with diameter 3 mm has resistance of 8 ohms. What is the resistance of 150 m of wire with diameter of 4 mm?\r
\n" ); document.write( "\n" ); document.write( "r $\"alpha%28l%2Fd%5E2%29\"$ \r
\n" ); document.write( "\n" ); document.write( "r = k*(l/d^2)\r
\n" ); document.write( "\n" ); document.write( "l = 100m diameter = 3mm = 0.003m , r = 8 $\"ohms\"$ \r
\n" ); document.write( "\n" ); document.write( "k = r * d^2/l\r
\n" ); document.write( "\n" ); document.write( "k = 0.003^2*8/100\r
\n" ); document.write( "\n" ); document.write( "k= 7.2*10^-7\r
\n" ); document.write( "\n" ); document.write( "150m, d=0.004m, k= 2.4*10^-7\r
\n" ); document.write( "\n" ); document.write( "r= 7.2^-7*150 /(0.004)^2\r
\n" ); document.write( "\n" ); document.write( "r= 9.35 ohms \n" ); document.write( "

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