Question

A cylinder of a material is 20m long and has a cross section of 1cm². If its resistance along the length be 20ohm, what will be it resistivity?
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Answer 1

Answer :

➥ The resistivity of a cylinder material = 0.0001 Ω m

Given :

➤ Length of a cylinder material (l) = 20 m

➤ Area of cross section (A) = 1 cm²

➤ Resistance of a cylinder material (R) = 20 Ω

To Find :

➤ Resistivity of a cylinder material (ρ) = ?

Solution :

◈ Area of cross section (A) = 1 cm² = 0.0001 m²

As we know that

$\tt{: \implies \rho = R \times \dfrac{A}{l}}$

$\tt{: \implies \rho = \cancel{20} \times \dfrac{0.0001}{ \cancel{20}}}$

$\bf{: \implies \underline{ \: \: \underline{ \purple{ \: \: \rho = 0.0001 \: \Omega \: m \: \: }} \: \: }}$

Hence, the resistivity of a cylinder material is 0.0001 Ω m.

Answer 2

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$\star\:\:\:\bf\large\underline\green{Given:—}$

☛︎Length of the cylinder material,L = 20 m

☛︎ Cross section, A = 1 cm² = 0.0001 m²

☛︎ Resistance, R = 20 Ω

$\star\:\:\:\bf\large\underline\green{To\:find:—}$

Resistivity, ρ = ?

$\star\:\:\:\bf\large\underline\green{Solution:—}$

$\boxed{\bf{\red{Formula\:used:—ρ=\frac{RA}{L}}}}$

Resistivity of the material ,

ρ = 20×0.0001/20 Ω

= 0.0001 Ω

Therefore, resistivity of the cylinder material is 0.0001 Ω

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