Question

Two wires of the same length and area made of two materials of resistivity ρ₁ and ρ₂ are connected in series to a source of potential V. The equivalent resistivity for the same area is:

Options

• ρ₁ + ρ₂

• `(ρ_1ρ_2)/(ρ_1 + ρ_2)`

• `((ρ_1 + ρ_2))/(ρ_1ρ_2)`

• `((|ρ_1 + ρ_2|)/21)`

Answer 1

`((ρ_1 + ρ_2))/(ρ_1ρ_2)`

Explanation:

For same length and area of cross-section `"R" ∝ ρ`.

For series combination, the equivalent resistance is

R_s = R₁ + R₂

⇒ ρ_s = ρ₁ + ρ₂