How is the resistance of a wire affected if radius is doubled

1.	How is the resistance of a wire affected if radius is doubled
Answer» Property to\xa0oppose the flow of electric current is called resistance. Its SI unit is ohms. If 1 V\xa0potential difference is there and 1 A\xa0current is flowing\xa0then it is said that there is 1 ohm resistance. {tex}\\therefore \\,R = \\frac{{\\rho l}}{A} \\Rightarrow R = \\frac{{\\rho l}}{{\\pi {r^2}}}{/tex}{tex}\\left[ {\\because A = \\pi {r^2}} \\right]{/tex}{tex}R\' = \\frac{{\\rho l}}{{\\pi {{(2r)}^2}}} = \\frac{{\\rho l}}{{\\pi {r^2}}} \\times \\frac{1}{4} = \\frac{R}{4}{/tex}Thus, resistance will decrease by four times, if radius of wire is doubled.

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