Question

Two copper wires have the same volume, but wire 2 is 10% longer than wire 1. The ratio of the resistances of the two wires R2/R1 is Group of answer choices 1.2. 1.1. 0.82. 0.91. 1.0.

Answer 1

Step-by-step explanation:

volume is same

π r₁² L₁ =π r₂²L₂

L₁ / L₂ = r₂² / r₁²

For resistance the formula is

R = ρ L / S where ρ is specific resistance , L is length and S is cross sectional area

R₁ = ρ L₁ / S₁

R₂ = ρ L₂ / S₂

Dividing

R₁ / R₂ = L₁ / L₂ x S₂ / S₁

= L₁ / L₂ x r₂² / r²₁

= L₁ / L₂ x L₁ / L₂

= L₁²/ L₂²

L₂ = 1.1 L₁ ( GIVEN )

= L₁²/ (1.1L₁)²

1 / 1.21

R₂ / R₁ = 1.21 .

= 1.2