Question

There are two strings made up of iron and silver of same thickness . length of iron string is 6 cm.find the length of silver wire whose resistance equal to resistance of the iron wireu

Answer 1

Answer:

37.5cm

Explanation:

Resistivity of silver = 1.6 × 10−8 Ωm

Resistivity of iron  = 10 x 10-8Ωm

Let resistance of silver wire be R and that of iron wire be R'

Let Area of cross section of silver wire be A and that of iron wire be A'

Given : R=R'

            A=A'

R'=$rho\frac{l}{A}$

  = 10 x 10⁻⁸ x 6/A'   (eq. 1)

R=$rho\frac{l}{A}$

  =1.6 × 10⁻⁸ x l/A'      (eq. 2)        (Since A=A')

From (1) and (2)

10 x 10⁻⁸ x 6/A' = 1.6 × 10⁻⁸ x l/A'

10 x 6 = 1.6 x l

l = 60 / 1.6

l = 37.5cm

Answer 2

Answer:

___________

Explanation:

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