Introduction to sound waves - class-VIII

Prefix in the word "Supersonic" is 'super', means superior to sound waves. Supersonic waves are faster than the sound wave in air.
Option "B" is correct.

We are given, frequency $f=300 Hz$, and velocity $v=336 ms^{-1}$,

Given that,

SInce rod is clamped at middle, therefore only nodes can form at that point, and at free end only antinode can form, therefore for fundamental mode of frequency,

From $v=n\lambda $ we find $\lambda\propto v$ because frequency n is constant .

Both ends are free and therefore antinodes are formed.
The relation between the wavelength of the wave and the length of the rod for fundamental frequency will be:

$\nu _1\lambda _1= \nu _1\lambda _1$ since $v= \nu\lambda$ is same for both a man and child.

$ \therefore 300 \times 1 =  \nu _2 \times  1.5$

Waves produced in a resonance tube are sound waves. Two sound waves in opposite direction interfere with each other to create resonance. As sound waves are longitudinal waves, waves produced are longitudinal stationary. 

From the formula, $v=f \lambda$

Sound cannot travel through a perfect vacuum. A vacuum is an area without any air, like space. So sound cannot travel through space because there is no matter for the vibration to work in.

Sound waves in air and any fluid medium are longitudinal waves because particles of the medium through which the sound is transported vibrate parallel to the direction that the sound waves moves.

A longitudinal wave has oscillations in the same direction as its motion.
Longitudinal waves, also known as l-waves, are waves in which the displacement of the medium is in the same direction as the direction of travel of the wave. Longitudinal waves are also called compressional waves or compression waves, because they produce compression and rarefaction when traveling through a medium.  In longitudinal waves, the displacement of the medium is parallel to the propagation of the wave. 

Sound is a sequence of waves of pressure which propagates through compressible media such as air or water. Sound propagates as longitudinal waves in gaseous medium. Longitudinal waves are the waves in which the displacement of the medium is in the same direction, or the opposite direction to the direction to the direction of propagation of wave.

In a wave if the particles of medium , vibrate perpendicular to the direction of wave motion (disturbance) then this wave is called a longitudinal wave .

Sound waves are longitudinal mechanical waves.

Particles of the sound waves vibrate in the direction of wave. So it is characterized under longitudinal waves.

Compressions are the regions of high density and rarefactions are regions of low density.These compressions and rarefactions result because sound is able to reflect off fixed ends and interfere with incident waves vibrates longitudinally; the longitudinal movement of air produces pressure fluctuations. 

Longitudinal waves are always characterized by particle motion being parallel to wave motion. A sound wave travelling through air is a classic example of a longitudinal wave. Transverse wave moves perpendicular to the direction of wave motion. Light waves are transverse in nature.

The waves in which the particles of the medium vibrate in a direction perpendicular to the direction of wave motion is known as transverse wave. Examples of these waves are: vibrations in strings, ripples on water surface and electromagnetic waves.

   Longitudinal waves propagate in a medium in the form of compressions and rarefactions . When pressure becomes high , medium particles come closer and a compression is formed and due to low pressure , rarefaction is formed .

When a sound travels through their medium, the molecules in the air oscillate to and fro about their mean positions in the direction of propagation of sound wave.

In case of longitudinal waves compressions and rarefactions are seen. Compressions are the regions of high density and rarefactions are regions of low density.In transverse waves generally crest and troughs are seen.

Sound is a longitudinal wave.  If the particles of a medium vibrate or oscillate to and fro about their equilibrium position along the direction of propagation of disturbance then the wave is called longitudinal wave.

Sound from a sound producing body travel through air to reach our ears by making regular compression and rarefaction.

Longitudinal waves are different from the others waves because in longitudinal waves particles of medium move in a direction parallel to direction of energy transport for longitudinal waves.

Graphical representation of longitudinal waves is the variation of pressure (y-axis) with the distance (x-axis). We know that, the pressure is higher at the point where the element of medium is compressed and the pressure is low where the element of medium is rarefied.
So, the wave forms a pressure peak at compression and pressure valley at rarefaction.

Sound waves are longitudinal waves which require a material medium (solid, liquid or gas) to propagate. So, sound waves cannot pass through a perfect vacuum.

If the particles of a medium vibrate or oscillate to and fro about their equilibrium position along the direction of propagation of disturbance then the wave is called longitudinal wave.

Graphical representation of longitudinal waves is the variation of
pressure (y-axis) with the distance (x-axis). We know that, the pressure
is higher at the point where the element of medium is compressed and
the pressure is low where the element of medium is rarefied.
So, the wave forms a pressure peak at compression and pressure valley at rarefaction.

All of the above are characteristics of Longitudinal waves

For transverse wave, cohesion is an important property in the medium through which the wave energy can be transported. Gas does not have such a cohesion property. Hence there is no chance for transverse waves to be propagated through gas medium. So the sound propagates in a gaseous medium by longitudinal wave.

Longitudinal waves are waves in which the motion of the individual particles of the medium is in a direction that is parallel to the direction of energy transport. Sound waves in air (and any fluid medium) are longitudinal waves because particles of the medium through which the sound is transported vibrate parallel to the direction that the sound wave moves.

Polarization is exhibited only by Transverse waves. Sound waves being longitudinal do not exhibit this phenomenon. 

When the tube is taken out of water, it acts as an open pipe of length L = 0.605 m. The fundamental frequency is f = v / (2L). Using the resonance data (50 cm length, 500 Hz source), the speed of sound is v = 4 * f * L_res = 4 * 500 * 0.5 = 1000 m/s. The fundamental frequency of the open pipe is 1000 / (2 * 0.605) = 826 Hz, which does not match the options well, suggesting a potential calculation error in the source question or specific assumptions about the end correction.

When wind blows in the direction opposite to sound propagation, the effective velocity of the sound wave relative to the ground decreases. This is a standard application of the principle of relative velocity for waves in a moving medium.

If we press and release a horizontal spring, it exhibits a confined motion of compression and rarefaction. So, it shows a replica of longitudinal waves. A swinging pendulum performs simple harmonic motion. A struck guitar string exhibits a replica of transverse waves. A rotating top exhibits rotational motion.

Sound waves are longitudinal waves because the disturbance of the medium particles is parallel to the direction of propagation of wave. The compression and rarefraction pulses produced moves in the direction parallel to the propagation direction of wave.

When a tuning fork is struck, the prongs vibrate transversely (perpendicular to the length of the prong). The stem, which is connected to the base of the prongs, vibrates longitudinally (along the axis of the stem) to transmit the sound to the resonance box.

Definition of Mach Number is $Ma=\frac{V _{body}}{V _{\mbox{sound in that medium}}}$.
Option "D" is correct.

When tuning fork is sounded by striking its one end on rubber pad 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. 

In sound waves vibration of particle is along the propagation of wave So it is longitudinal and in other options all are transverse wave as vibration of particle is perpendicular to the propagation of wave.  

Sound waves are longitudinal waves. It needs a medium to propagate. Sound waves are example of mechanical waves, not electromagnetic waves. Electromagnetic waves are created by the vibration of an electric charge.

Longitudinal waves, also known as l-waves, are waves in which the displacement of the medium is in the same direction as, or the opposite direction to, the direction of travel of the wave. Longitudinal waves are also called compression waves or compression waves, because they produce compression and rarefaction when traveling through a medium.  In longitudinal waves, the displacement of the particle's is parallel to the propagation of the wave. 

Longitudinal waves, also known as l-waves, are waves in which the displacement of the medium is in the same direction as the direction of travel of the wave. Longitudinal waves are also called compressional waves or compression waves, because they produce compression and rarefaction when traveling through a medium.

Sound is a mechanical wave that results from the back and forth vibration of the particles of the medium through which the sound wave is moving. If a sound wave is moving from left to right through air, then particles of air will be displaced both rightward and leftward as the energy of the sound wave passes through it. The motion of the particles is parallel to the direction of the energy transport. This is what characterizes sound waves in air as longitudinal waves.
Longitudinal waves, also known as l-waves, are waves in which the displacement of the medium is in the same direction as, or the opposite direction to, the direction of travel of the wave. Longitudinal waves are also called compressional waves or compression waves, because they produce compression and rarefaction when traveling through a medium.  In longitudinal waves, the displacement of the medium is parallel to the propagation of the wave.

Given that, 

Let,

Mechanical waves (longitudinal waves and transverse waves) are waves which propagate through a material medium (solid, liquid or gas) at a wave speed which depends on the elastic and inertial properties of that medium. 
The transverse waves depends on the rigidity of the medium hence, can propagate through solid and liquid medium but not through gases.
The longitudinal waves depends on resistance to compression or volume elasticity of the medium hence, can propagate through solid, liquid and gases.

$\displaystyle x = v.t = v \times \dfrac{no \ of \ complete \ vibration }{frequency \ of fork}=325$ x $\displaystyle\frac{36}{384} = 33 m$

According to the Avogadro's law , at same temperature and pressure the number of molecules of different gasses are equal. Therefore density will not change in either case of neon or water vapor. And the speed of sound waves is a function of density and temperature. So in this case doesn't matter.
Option "D" is correct. 

Because water molecules have less mass than the average air molecules $(N _2 (28 \text{amu}),$ while water $H _2O (18 amu)).$ But It will happen if and only if the pressure is unchanged. Given that dry and humid air are both under the same pressure then we have smaller density for humid air.
And velocity of sound waves$,v,$ in a medium is given by,

When the tuning fork is set into vibration, the stem of tuning fork vibrate  up and down with longitudinal vibrations hence, when the stem of a vibrating tuning fork is pressed a sounding board, then longitudinal vibrations are communicated through stem to the board.

Longitudinal Waves are generated when slinky is stretched out in a horizontal direction and first coils are vibrated horizontally