Tag: study of sound

Questions Related to study of sound

A longitudinal wave consists of :

physics study of sound types of waves sound as a wave of disturbance sound waves are longitudinal waves

  1. crest and trough in the medium

  2. compression and rarefraction in the medium

  3. both (a) & (b)

  4. nither (a) nor (b)

Show answer
Correct Option: A

Find the incorrect statement

physics study of sound types of waves sound as a wave of disturbance sound waves are longitudinal waves

  1. Ultrasound can be used to determine the sex of the unborn baby (embryo)

  2. Ultrasound can be used to keep away rodents in cold storage

  3. Ultrasound can be used to detect even bone fractures

  4. Ultrasound travels faster than sound

Show answer
Correct Option: C,D
Explanation:

Ultrasound frequency used for imaging is about $5 MHz.$
The corresponding wavelength is $\lambda = \dfrac{v}{\nu}=\dfrac{1540 \text{m/s}}{5\times 10^6} = 0.3mm$ 
Here speed of ultrasound in tissue is taken to be $1540 m/s$.
So ultrasound can not be used for bone fractures as it bone fracture can have size of few microns.
Ultrasound does not travel faster than sound. Sound speed does not depend on frequency.
$v=\nu \lambda$ if $\nu$ is higher, $\lambda$ becomes smaller and $v$ remains constant.

A metal bar clamped at its center resonates in its fundamental mode to produce longitudinal waves of frequency 4 kHz.Now the clamp is moved to one end. If ${f _1}\;{\text{and}}\;{f _2}$ be the frequencies of first overtone and second overtone respectively then, 

physics study of sound types of waves sound as a wave of disturbance sound waves are longitudinal waves

  1. $3{f _2} = 5{f _1}$

  2. ${f _2} = 2{f _1}$

  3. $3{f _1} = 5{f _2}$

  4. $2{f _2} = {f _1}$

Show answer
Correct Option: A
Explanation:

$\begin{array}{l} { f _{ 1 } }=3f \ { f _{ 2 } }=5f \ \Rightarrow 5{ f _{ 1 } }=3{ f _{ 2 } } \ Hence, \ option\, \, A\, \, is\, \, correct\, \, answer. \end{array}$

A longitudinal wave is reflected from the surface of a rigid wall. Its phase changes by :

physics study of sound types of waves sound as a wave of disturbance sound waves are longitudinal waves

  1. 0 rad

  2. $\pi $ rad

  3. $\pi $/2 rad

  4. 2 $\pi $ rad

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Correct Option: B

In a stationary wave represented by $y = a \sin wt \cos kx$, amplitude of the component progressive wave is

physics study of sound types of waves sound as a wave of disturbance sound waves are longitudinal waves

  1. $\frac{a}{2}$

  2. $a$

  3. $2a$

  4. $a^2$

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Correct Option: A

Which of the following equations represents a wave travelling along  $Y$-axis ?

physics study of sound types of waves sound as a wave of disturbance sound waves are longitudinal waves

  1. $x = A \sin ( k y - \omega t )$

  2. $y = A \sin ( k x - \omega t )$

  3. $y = A \sin k y \cos \omega t$

  4. $y = A \cos k y \sin \omega t$

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Correct Option: A

How many types of mechanical waves exist in physics?

physics study of sound types of waves sound as a wave of disturbance sound waves are longitudinal waves

  1. one

  2. two

  3. three

  4. four

Show answer
Correct Option: C
Explanation:

There are 3 types of mechanical waves
1.Transverse Waves
2.Longitudinal Waves
3.Surface Waves

State whether the given statement is True or False :

If a pebble is thrown into the water the ripples on the surface of water are created due to translatory motion of the water particles.

physics study of sound types of waves sound as a wave of disturbance sound waves are longitudinal waves

  1. True

  2. False

Show answer
Correct Option: B
Explanation:

when the pebble is thrown in water the disturbance created travels in all outwards directions over the surface of the water in the form of ripples these ripples are circular in shape .

so the statement is false .
so answer is B.

When a tuning fork vibrates, the waves produced in the stem are:

physics study of sound types of waves sound as a wave of disturbance sound waves are longitudinal waves

  1. longitudinal

  2. transverse

  3. both (a) and (b)

  4. none of these

Show answer
Correct Option: A
Explanation:

When tuning fork is sounded by striking its one end then the prongs vibrate in and out and stem vibrate up and down. Hence, vibration of prongs are transverse and those of stem are longitudinal. 

Hence Option A is correct

Transverse waves cannot travel through

physics study of sound types of waves sound as a wave of disturbance sound waves are longitudinal waves

  1. An iron rod

  2. Hydrogen gas

  3. A stretched nylon string

  4. Lubricating oil

Show answer
Correct Option: B
Explanation:

Transverse waves cannot propagate in a gas because there is no mechanism for driving motion perpendicular to the propagation of the wave.

so the answer is B.