⇦ | ⇨ |
The masses of three wires of copper are in the ratio 1:3:5 and lengths are in the ratio 5:3:1. Then the ratio of their electrical resistance are
Options
(a) (1:3:5)
(b) (5:3:1)
(c) (1:15:25)
(d) (125:15:1)
Correct Answer:
(125:15:1)
Explanation:
Let A₁, A₂ and A₃ be the area of cross-section of three wires of copper of masses m₁,m₂ and m₃ and length l₁,l₂ and l₃ respectively.
m₂ = 3m, m₃ = 5m, l₁ = 3l, l₃ = l
Since Mass = Volume density
.·. m = A₁ × 5l × ρ —-(i)
3m = A₂ × 3l × ρ —(ii)
5m = A₃ × 1l × ρ —(iii)
From (i) and (iii), we get
A₂ = 5A₁
From (i) and (iii), we get
A₃ = 25 A₁
.·. R₁ = ρl₁ / A₁ = ρ5l / A₁, R₂ = ρl₂ / A₂ = ρ3l / A₁ = (3 / 25) R₁
R₃ = ρl₃ / A₃ = ρl / 25 A₁ = (R₁ / 125) = 125 : 15 : 1
Related Questions: - Which one of the following is not due to total internal reflection?
- An automobile moves on a road with a speed of 54 km h⁻¹. The radius of its wheels
- To convert a 800 mV range millivoltmeter of resistance 40Ω into an ammeter of 100 mA
- A series R-C circuit is connected to an alternating voltage source. Consider two
- The ratio of minimum wavelengths of Lyman and Balmer series will be
Topics: Current Electricity
(136)
Subject: Physics
(2479)
Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score
- Which one of the following is not due to total internal reflection?
- An automobile moves on a road with a speed of 54 km h⁻¹. The radius of its wheels
- To convert a 800 mV range millivoltmeter of resistance 40Ω into an ammeter of 100 mA
- A series R-C circuit is connected to an alternating voltage source. Consider two
- The ratio of minimum wavelengths of Lyman and Balmer series will be
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
Leave a Reply