Question

The resistance of a wire 2.5 m long and 0.9 mm in diameter is 0.07 ohm. What is the resistivity of the material of the wire?

Answer 1

l=1m ,d=0.2mm=>r=0.1mm and R=10 ohm

by using the formula,  

R= p౹/ A

= p౹/ πr²

therefore, p= Rπr²/l

= 10× 3.14×( 0.1× 10 -³)²

= 10× 3.14× 0.1×0.1× 10 to the power -6

= 0.314× 10 to the power-6

= 3.14× 10 to the power-7 ohm- m

Answer 2

here , it is Given that:

l=1m ,d=0.2mm=>r=0.1mm and R=10 ohm

by using the formula,

R= p౹/ A

= p౹/ πr²

therefore, p= Rπr²/l

= 10× 3.14×( 0.1× 10 -³)²

= 10× 3.14× 0.1×0.1× 10 to the power -6

= 0.314× 10 to the power-6

= 3.14× 10 to the power-7 ohm- m

hence, the resistivity of the conductor is 3.14× 10 to the power-7 ohm- m
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