Tag: beats in sound waves

Questions Related to beats in sound waves

The musical interval between tube two tine of frequency $400\ Hz$ and $200\ Hz$ is:

physics beats in sound waves

  1. $2$

  2. $200$

  3. $1$

  4. $none\ of\ these$

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Correct Option: A

A key of mechanical piano is first struck gently and then struck again but much harder this time. In the second case :

physics beats in sound waves

  1. sound will be louder but pitch will not be different

  2. sound will be louder and the pitch will also be higher

  3. sound will be louder but pitch will be lower

  4. both loudness and pitch will remain unaffected

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Correct Option: A
Explanation:

Loudness or softness of a sound is determined basically by its amplitude. The amplitude of the sound wave depends upon the force with which an object is made to vibrate. If we strike a table lightly, we hear a soft sound because we produce a sound wave of less energy (amplitude). Pitch depends upon frequency received by the human ear.

The characteristics of sound with the help of which we can distinguish between a SHRILL note and a GRAVE note is

physics beats in sound waves

  1. Loudness

  2. Pitch

  3. Quality

  4. Intensity

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Correct Option: B

How Jal Tarang produces sound?

physics beats in sound waves

  1. In Jal-tarang musical instrument the cup containing minimum water produces the sound of lowest frequency.

  2. In Jal-tarang musical instrument the cup containing minimum water produces the sound of lowest pitch.

  3. In Jal-tarang musical instrument the cup containing minimum water produces the sound of lowest frequency. As the amount of water in the cup goes on increasing, the frequency of the sound produced also goes on increasing.

  4. all

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Correct Option: D
Explanation:

n Jal-tarang musical instrument the cup containing minimum water produces the sound of lowest frequency or lowest pitch. As the amount of water in the cup goes on increasing, the frequency (or the pitch) of the sound
produced also goes on increasing.

Beats are heard at the rate of $12$ every $5$ seconds when two open organ pipes of lengths $84\ cm$ and $85\ cm$ are sounded together in their fundamental modes. Find the velocity of sound in air. (An open organ pipe has an antinode at each end.

physics beats in sound waves

  1. $342.7\ m/s$.

  2. $300.7\ m/s$.

  3. $350.7\ m/s$.

  4. $400.7\ m/s$.

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Correct Option: A

An under water swimmer sends a sound signal to the surface. It is produces 5 betas/sec when compared with fundamental tone of a pipe of $20$ cm length closed at one end what is wavelength of sound in water. (take V water=$1500 m/sec$ Vair=$360 m/sec$)

physics beats in sound waves

  1. $3.3 m$ or $3.37 m$

  2. $4.4 m$ or $4.47 m $

  3. $2.5 m$ or $2.7 m$

  4. $1 m$ or $1.7 m$

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Correct Option: A

identify the part which vibrates to produce sound in the following instruments.

physics beats in sound waves

  1. tabla or dholak

  2. flute

  3. tuning fork

  4. sitar

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Correct Option: C

Two sound sources are moving in opposite direction with velocity $v _1$ and $v _2$ $(v _1>v _2)$. Both are moving away from a stationary observer.the frequency of both the source is $900\ Hz$. What is the value of $v _1 - v _2 $  so that the beat frequency observed will be $6\ Hz$  ?


Speed of sound =$300\ ms^{-1}$

physics superposition of waves-1: interference and beats distinction between interference and beats beats and its applications beats in sound waves

  1. $1\ ms^{-1}$

  2. $4\ ms^{-1}$

  3. $3\ ms^{-1}$

  4. $2\ ms^{-1}$

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Correct Option: D
Explanation:

$f _1 = 900(\dfrac{300}{300+v _1})$

$\implies f _1= 900(1+ \dfrac{v _1}{300})^{-1}$
$\implies f _1 = 900 - 3v _1$
Similarly 
$f _2 = 900 - 3v _2$
So,
$f _1 -f _2 = 6$
$3(v _1 - v _2)= 6$
$\implies v _1 - v _2 = 2\ ms^{-1}$

Sound waves of equal amplitude wave frequency $(n-1),n _1(nH^1)$. They superinpose to give Beat. The no of Beats poduced per sec cuPll be:

physics superposition of waves-1: interference and beats distinction between interference and beats beats and its applications beats in sound waves

  1. l

  2. 0

  3. 3

  4. 2

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Correct Option: D

A sources of sonic oscillations with frequency n= $1700$ Hz and a receiver are located on the same normal to a wall. Both the source and receiver are stationary, and the wall recedes from the source with velocity u= $6.0$ cm/s. Find the beat frequency registred by the receiver. The velocity of sound is equal to $v= 340$ m/s.

physics superposition of waves-1: interference and beats distinction between interference and beats beats and its applications beats in sound waves

  1. $0.2$ Hz

  2. $0.3$ Hz

  3. $0.4$ Hz

  4. $0.6$ Hz

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Correct Option: D