Two wires of equal length and equal diameter and having resistivities ρ₁ and ρ₂

⇦

⇨

Two wires of equal length and equal diameter and having resistivities ρ₁ and ρ₂ are connected in series. The equivalent resistivity of the combination is

Options

(a) ρ₁+ρ₂/2
(b) ρ₁+ρ₂
(c) ρ₁ρ₂/ρ₁+ρ₂
(d) √ρ₁ρ₂

Correct Answer:

ρ₁+ρ₂/2

Explanation:

The resistance of two wires are

R₁ = ρ₁ (l / A) and R₂ = ρ₂ (l / A)

Now, equivalent resistance of series connection of wire

Req = R₁ + R₂ = ρ₁ (l / A) + ρ₂ (l / A) = (l / A) (ρ₁ + ρ₂)

The equivalent resistance Req can be given by Req = ρ(eq) (l / A)

⇒ ρ(eq) (l / A) = (l / A) (ρ₁ + ρ₂)

Hence, ρ(eq) = (ρ₁ + ρ₂) / 2

Related Questions:

1. If the focal length of a concave mirror is 50 cm, then where should the object
2. The angle between the two vectors A = 3i+4j+5k and B = 3i+4j-5k will be
3. A particle has initial velocity (2i⃗+3j⃗) and acceleration (0.3i⃗+0.2j⃗). The magnitude
4. A body of mass 1.0 kg is falling with an acceleration of 10 ms⁻².
5. Three identical spheres, each of mass 3 kg are placed touching each other

Topics: Current Electricity (136)
Subject: Physics (2479)

---

Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score

18000+ students are using NEETLab to improve their score. What about you?

Solve Previous Year MCQs, Mock Tests, Topicwise Practice Tests, Identify Weak Topics, Formula Flash cards and much more is available in NEETLab Android App to improve your NEET score.

---

Share this page with your friends