Question

What will be the resistivity of a metal wire of 2m length and 0.6mm in diameter if the resistance of the wire is 50ohm

Answer 1

Given :-

• length of metal wire , l = 2 m
• diameter of metal wire = 0.6 mm
• resistance of the wire , R = 50 Ω

To find :-

• Resistivity of metal wire , ρ = ?

Formula required :-

● R = ρ × l / A

(where R is resistance , l is length , ρ is the resistivity and A is the area of cross section of any conductor)

Solution :-

Let's first calculate the Area of cross section of wire

diameter of wire = 0.6 mm

radius of wire = 0.3 mm = 0.3 × 10⁻³ m

so,

→ area of cross section = π (radius)²

→ area of cross section , A = 22/7 × (0.3×10⁻³)²

→ area of cross section , A = 0.3 × 10⁻⁶ m²  (approx.)

Now,

Using the formula  R = ρ × l / A

→ R =  ρ × l / A

→ 50 = ρ × 2 / (0.3 × 10⁻⁶)

→ ρ = (50 × 0.3 × 10⁻⁶) / 2

→ ρ = 7.5 × 10⁻⁶  Ω m    (Ans.)

Hence,

Resistivity of wire will be

7.5 × 10⁻⁶ ohm metre .

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• Electrical resistivity is defined as the resistance of material per unit of length and per unit of area of cross section at a given temperature.

• Electrical resistivity depends on the material of conductor and the temperature of conductor.

• S.I. unit of electrical resistivity is ohm metre ( Ω m ).

• Resistivity is generally denoted by Greek letter ρ (called rho) .

_____________________

Answer 2

Answer:

yess i think so above ans is correct

thanks bro

mujhe bhi esi question mai doubt tha.....

thanks