Question

the resistance of a metallic wire is 10ohm , length 2m and diameter is 0.5mm find the resistivity of the wire ,what happens to the resistance, resistivity of the wire when the length is doubled
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Answer 1

resistivity of wire is 3.9 ×10⁻⁶ohm.m

Explanation:

• Resistivity is symbolised in greek letter called rho which is equal to the resistance of wire( R )multiplied by area of cross section of a wire( A )and devided by length( L ).

• ρ= R×A/L

        ρ=10 ohm×0.25 ×10⁻⁶m/ 2 m

        ρ =3.9 ×10⁻⁶ohm.m  

• If the wire length is doubled then resistance will be doubled because it is directly propotional to the length while resistivity depends on the nature and temperature of the conductor but do not depend on the length so it will be not effected

Answer 2

Given :

Resistance of a metallic wire I = 10ohm  

Length =2m  

Diameter = 0.5mm  

To find :  

1.Resistivity of the wire  

2.What happens to the resistance, resistivity of the wire when the length is doubled.

Solution :

By using formula, we get :

ρ= $R\times\frac{A}{L}$

ρ=10  $\times$ 0.25 ×10⁻⁶ ohm.m  

ρ=3.9 ×10⁻⁶ohm.m  

Resistivity of the wire when the length is doubled the resistance will be doubled because it is directly propotional to the length while resistivity depends on the nature and temperature of the conductor but do not depend on the length so it will be not effected .