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. The total energy of an electron in the first excited state of hydrogen atom
2. A conductor of length 5 cm is moved parallel to itself with a speed of 2 m/s,
3. 300j work is done in sliding a 2kg block up an inclined plane of height 10m
4. If a body travels half the distance with velocity v1 and the next half with velocity v2
5. Bohr’s postulates quantizes

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