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A copper wire has diameter \(0.5\ mm\) and resistivity of \(1.6 × 10^{–8} Ω m\). What will be the length of this wire to make its resistance 10 ? How much does the resistance change if the diameter is doubled?
[Note: Enter the final answer up to one decimal place.]
\(\rho\) \(=\) \(1.6 × 10^{–8} Ω m\)
Diameter, \(d\ =\) \(0.5\ mm\)
In terms of \(metre\), the value is .
The formula for specific resistance is
Area of cross-section of the wire is
(Write in short form)
On substituting the known values, we get the length of this wire as \(l\ =\) .
If the diameter of the wire is doubled, then the new diameter is .
On substituting the known values, the new resistance is
\(R^{'}\) \(=\)
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