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Resistance of a metal wire of length 1 \(m\) is 26 Ω at \(20°C\). If the diameter of the wire is \(0.3\ mm\), what will be the resistivity of the metal at that temperature? Using table, predict the material of the wire.
  
Material's nature
Material
Resistivity of material
(\(\Omega\ m\)) 
Conductors
Silver
  
Copper
 
Aluminium
 
Tungsten
 
Nickel
 
Iron
 
Chromium
  
Mercury
  
Manganese
\(1.60\times{10^{-8}}\)
 
\(1.62\times{10^{-8}}\)
 
\(2.63\times{10^{-8}}\)
 
\(5.20\times{10^{-8}}\)
 
\(6.84\times{10^{-8}}\)
 
\(10.0\times{10^{-8}}\)
 
\(12.9\times{10^{-8}}\)
 
\(94.0\times{10^{-8}}\)
 
\(1.84\times{10^{-6}}\)
Alloys
  
Constantan
  
Manganin
  
Nichrome
  
 
\(49\times{10^{-6}}\)
 
\(44\times{10^{-6}}\)
 
\(100\times{10^{-6}}\)
 
Insulators
Glass
 
Hard rubber
  
Ebonite
  
Diamond
 
Dry paper
\(10^{10}\) to \(10^{14}\)
 
\(10^{13}\) to \(10^{16}\)
 
\(10^{15}\) to \(10^{17}\)
 
\(10^{12}\) to \(10^{13}\)
 
\(10^{12}\)
 
[Note: Enter the answer up to two decimal places by rounding off the third decimal value.]
 
\(L\) \(=\) 1 \(m\)
 
\(R\) \(=\) 26 Ω
 
\(d\) \(=\) \(0.3\ mm\)
 
On converting \(millimetre\) to \(metre\), we get  \(\times{10^{-4}}\ m\).
 
The formula to calculate the resistivity of a material is
 
ρ=iii
 
The formula to calculate the area of cross-section of the wire when diameter is given.
 
A=πiii
 
On substituting the known values in the formula, we get the value of resistivity,
 
\(\rho\) \(=\)  ×106Ωm
 
From the given table, it is seen that it is the resistivity of .