Question

the resistance of a metal wire of length 1m is 26 ohm at 20 degree celsius .if the diameter of the wire is 0.03 cm what will be the resistivity of the metal at that temperature?​

Answer 1

Answer:

Resistance , R = 26Ω

Length of wire , L = 1m

diameter of circular part of wire ,d = 0.3mm = 0.3 × 10⁻³m

so, base area of wire , A = πr² = πd²/4 [ ∵d = 2r]

= 3.14 × (0.3 × 10⁻³)²/4m²

= 3.14 × 9 × 10⁻⁸/4 m²

= 28.26/4 × 10⁻⁸ m² = 7.06 × 10⁻⁸ m²

Now, use formula,

R = ρL/A

Here, R is the resistance, ρ is the resistivity , L is the length of wire and A is the base area of it .

So , ρ = RA/L = 26Ω × 7.06 × 10⁻⁸m²/1m

ρ = 1.8356 × 10⁻⁶ Ωm

Hence, resistivity is 1.8356 × 10⁻⁶ Ωm at 20°C

PLZ MARK AS BRIANLIEST,FLW ME AND THX FOR THE SUPERB QUESTION

Answer 2

Answer:

R=26 Ω

l=1m

d−0.3mm

r=2d=20.3×10−3=0.15×10−3m

A=πr2=3.14×(0.15×10−3)2=0.071×10−6m2

R=AρL

or ρ=lRA=126×0.071×10−6=1.84×10−6Ωm