what will be the length of a nichrome wire of resistance 5 ohm if the length of similar wires of 120 cm and resistance of 2.5. why
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Wire A.
Length = l.
Radius =r.
Area =pie r2.
R1= rho x l /pie r2.
Wire B.
Length = 2l.
Radius = 2r.
Area = pie 4r2.
R2= rho x 2l/pie 4r2=rho x l /pie x 2r2.
total resistance.
1/Rp= 1/R1+1/R2.= pie r2/rho x l+2 pie r2/ rho x l.=3 pie r2/rho x l.
Rp= rho x l/ 3 pie x r2.
ratio = Rp/ R1= rho /3 pie r2divided by rho x l / pie x r2.
Rp / R1= 1 : 3.
Hope it helps you.
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