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. A point charge q is situated at a distance r on axis from one end of a thin
2. The radioactivity of a certain material drops to 1/16 of the initial value in 2 hours.
3. A body of mass 2 kg is kept by pressing to a vertical wall by a force of 100 N
4. The optical path of a monochromatic light is same if it goes through 4.0 cm
5. The diameter of the eye ball of a normal eye is about 2.5 cm. The power of the eye

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