Question

Resistance of metal wire of length 2m is 30 ohm at 25 degree celsius.if diameter of the wire is o.6mm,then what will be resistivity of the metal at that temperature

Answer 1

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Answer 2

Answer: The resistivity of the metal is $\rho = 4.239\times10^{-6}\ \Omega m$.

Explanation:

Given that,

length of wire l = 2 m

Resistance R = 30 ohm

diameter d =0.6 mm

Radius = 0.3 mm

We know that,

The resistivity of the metal is

$R = \dfrac{\rho l}{A}$

$\rho = \dfrac{RA}{l}$....(I)

Put the value of R,l and A in equation (I)

$\rho = \dfrac{30\times3.14\times3\times3\times10^{-8}}{2}$

$\rho= 423.9\times10^{-8}\ \Omega m$

$\rho = 4.239\times10^{-6}\ \Omega m$

Hence, The resistivity of the metal is $\rho = 4.239\times10^{-6}\ \Omega m$.