Question

 A wire is 1.5 m long, 0.3 mm in diameter and has resistance of 15Ω. Calculate its resistivity​

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Current Electricity

Electrical Resistance & Resistivity

A wire is 1.0 m long , 0.2 ...

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Asked on December 26, 2019 by

Mahalakshmi Kottu

A wire is 1.0 m long , 0.2 mm in diameter and has a resistance of 10 Ω. Calculate the resistivity of its material.

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ANSWER

Given,

l=0.1m=1000mm

d=0.2mm∴radius(r)=

2

0.2

=0.1mm

R=10Ω

To find,

Resistivity(ρ)

ρ=R

l

A

where,

R= Resistance

l= Length of wire

A= Cross sectional area of wire

Cross sectional area of cylinder (A)=Πr

2

⇒A=π×(0.1)

2

⇒A=0.0314mm

2

∴ρ=10(

1000

0.0341

)

⇒ρ=0.000314Ω−mm

⇒ρ≃3.14×10

−7

Ω−m

So, the resistivity of the material is equal to 3.14×10

−7

Ω−m