| ⇦ | 
| ⇨ |
Masses of 3 wires of same metal are in the ratio 1:2:3 and their lengths are in the ratio 3:2:1. The electric resistances are in the ratio
Options
(a) (1:4:9)
(b) (9:4:1)
(c) (1:2:3)
(d) (27:6:1)
Correct Answer:
(27:6:1)
Explanation:
Mass = volume × density = A.l.d
Ald = m
Resistance R = ρl / A = ρl / (m/ld) = dρ (l²/m)
Now, R₂ / R₁ = (ρd / ρd) )(l₂² / l₁²) (m₁/m₂)
= (2/3)² × (1/2) = 2 / 9
⇒ R₂ = (2 / 9) R₁
Again R₃ / R₁ = (ρd / ρd) )(l₃² / l₁²) (m₁/m₃)
= (1/3)² × (1/3) = 1 / 27
⇒ R₃ = (R₁ / 27)
.·. R₁ : R₂ : R₃ = R₁ : (2/9) R₁ : (R₁/27) = 27 : 6 : 1
Related Questions: - An electromagnetic wave of frequency v = 3.0 MHz passes from vacuum into
- Electrons used in an electron microscope are accelerated by a voltage of 25 kV
- The work function for metals A,B abd C are respectively 1.92 eV,2.0 eV and 5 eV.
- Which of the following, is a vector quantity?
- A round disc of moment of inertia i₂ about its axis perpendicular to its plane
Topics: Current Electricity
(136)
Subject: Physics
(2479)
Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score
- An electromagnetic wave of frequency v = 3.0 MHz passes from vacuum into
- Electrons used in an electron microscope are accelerated by a voltage of 25 kV
- The work function for metals A,B abd C are respectively 1.92 eV,2.0 eV and 5 eV.
- Which of the following, is a vector quantity?
- A round disc of moment of inertia i₂ about its axis perpendicular to its plane
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