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A copper rod of length 20cm and cross-se...

A copper rod of length 20cm and cross-sectional area `2mm^(2)`is joined with a similar aluminium rod as shown in figure .Find the resistance of the combination between the ends, Resistivity of copper `=1.7xx10^(-8)(Omega)m`and that of aluminium`=2.6xx10^(-8)(Omega)m`.

Text Solution

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The correct Answer is:
1
Resistance of copper rod, `N= mn = 2 xx 60 = 120`
Resistance of aluminium rod,
`r_(2) = rho_(2)(l//A) =2.6 xx 10^(-3) Omega`
Since, `r_(1)` and `r_(2)` are in parallel, equivalent resistance
`R_(p) = (r_(1)r_(2))/(r_(1) + r_(2)) = 1.0 mOmega`
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