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A wire of 10 ohm resistance is stretched to thrice its original length. What will be its (i) new resistivity and (ii) new resistance? |
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Answer» SOLUTION :(i) Resistivity `rho` remains unchanged because it is the property of the material of the wire. (ii) In both cases, volume of wire is same, so `V=A.l.=Al` `(A.)/(A)=(l)/(l.)=(l)/(3L)=(1)/(3)"" [because l.=l+2l=3l]` `therefore (R.)/(R )=(rho(l.)/(A.))/(rho (l)/(A))=(l.)/(l)XX(A)/(A.)=(3)/(1)xx(3)/(1)=9` HENCE, `R.=9R=9xx 10=90Omega` |
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