Science, asked by Asad7184, 1 year ago

the resistivity of copper is 1.76 x 10-8 ohm metre the radius of the wire is 1mm, calculate the lenght of wire needed for having resistance of 10.5 ohm.

Answers

Answered by rishu92
132
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R = ρl/A
⇒ R = ρl/πr2 ...(1)
Where,
R = 10.5 Ω, ρ = 1.76 * 10-8Ωm and radius r = 1mm = 1 * 10-3m
From equation (1)
length l = πr2R/ρ
On putting all values you will get
length l = 1873.3 m

karandhamija031: Plz explain me in detail
Answered by anjali13lm
2

Answer:

The length, L, of the wire measured is 1873.2m.

Explanation:

Given,

The resistivity of the copper wire, ρ = 1.76\times 10^{-8}\Omega -m

The radius of the wire, r = 1mm = 10^{-3} m.

The resistance of the wire, R = 10.5 \Omega

The length of the wire, L =?

Now,

  • The length of the wire can be calculated by the resistivity formula given below:
  • \rho = \frac{RA}{L}    -------equation (1)

Here, A = area of cross- section = \pi r^{2}

After putting the A = \pi r^{2} in equation (1), we get:

  • \rho = \frac{R\pi r^{2} }{L}

Thus,

  • L = \frac{R\pi r^{2} }{\rho}

After putting the given values in the equation, we get:

  • L = \frac{10.5\times 3.14\times  (10^{-3}) ^{2} }{1.76\times 10^{-8} }
  • L = \frac{32.97\times 10^{-6} }{1.76\times 10^{-8} }
  • L = 1873.2 m

Hence, the length of the wire, L = 1873.2m.

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