Question

A wire of length 150 cm and of resistance 4.5Ω has area of cross section 0.04 cm2. Calculate the resistivity of wire in SI unit.

Answer 1

Given :

• length of wire, L = 150 cm = 1.5 m
• Resistance of wire, R = 4.5 Ω
• area of cross section of wire, A = 0.04 cm² = 0.04 × 10⁻⁴ m²

To find :

• Resistivity of wire in its SI unit, ρ = ?

Knowledge required :

• Relation b/w resistivity (ρ) , Resistance (R) , Length of conductor (L) and area of cross section of conductor (A)

      ρ = R A / L

• SI unit of resistivity is ohm - metre . ( Ω m )

Calculation :

Using formula

→ ρ = R A / L

→ ρ = ( 4.5 ) ( 0.04 × 10⁻⁴ ) / ( 1.5 )

→ ρ = 0.12 × 10⁻⁴ Ω m

Therefore,

Resistivity of wire is 0.12 × 10⁻⁴ Ω m .

Answer 2

Answer:

0.12 × 10⁻⁴ Ω m

Explanation:

length of wire, L = 150 cm = 1.5 m

Resistance of wire, R = 4.5 Ω

area of cross section of wire, A = 0.04 cm² = 0.04 × 10⁻⁴ m²

To find :

Resistivity of wire in its SI unit, ρ = ?

Knowledge required :

Relation b/w resistivity (ρ) , Resistance (R) , Length of conductor (L) and area of cross section of conductor (A)

     ρ = R A / L

SI unit of resistivity is ohm - metre . ( Ω m )

Calculation :

Using formula

→ ρ = R A / L

→ ρ = ( 4.5 ) ( 0.04 × 10⁻⁴ ) / ( 1.5 )

→ ρ = 0.12 × 10⁻⁴ Ω m

Therefore,

Resistivity of wire is 0.12 × 10⁻⁴ Ω m.