Two sources of sound placed close to each other are emitting progressive waves

⇦

⇨

Two sources of sound placed close to each other are emitting progressive waves given by y₁ = 4 sin 600 πt and y₂ = 5 sin 608 πt. An observer located near these two sources of sound will hear:

Options

(a) 4 beats per second with intensity ratio 25 : 16 between waxing and waning
(b) 8 beats per second with intensity ratio 25 : 16 between waxing and waning
(c) 8 beats per second with intensity ratio 81 : 1 between waxing and waning
(d) 4 beats per second with intensity ratio 81 : 1 between waxing and waning

Correct Answer:

4 beats per second with intensity ratio 81 : 1 between waxing and waning

Explanation:

2πf₁ = 600π , f₁ = 300 …(1)
2πf₂ = 608π , f₂ = 304 …(2)
| f₁ – f₂ | = 4 beats
Iₘₐₓ / Iₘ.ₙ = (A₁ + A₂)² / (A₁ – A₂)² = (5 + 4)² / (5 – 4)² = 81/1
where, A₁ , A₂ are amplitudes of given two sound wave.

Related Questions:

1. If the self inductance of 500 turn coil is 125 mH, then the self inductance
2. An insulated container of gas has two champers seperated by an insulating partition.
3. Two wires of equal length and equal diameter and having resistivities ρ₁ and ρ₂
4. If the earth shrink such that its mass does not change but radius decreases to one
5. Energy stored in the coil of a self inductance 40 mH carrying a steady current of 2A

Topics: Waves (80)
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