Tag: world of sounds

Quizzes (14) Questions (102)

Questions Related to world of sounds

Multiple choice physics world of sounds characteristics of sound wave time period, frequency and amplitude of sound sound waves are longitudinal waves

How is the frequency of a wave related to its time period?

  1. $\ v=\displaystyle\frac{1}{T}$
  2. $\ T=\displaystyle\frac{1}{v}$
  3. $\ v T=\displaystyle{1}$

  4. All the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Frequency is the number of occurrences of a repeating event per unit time. The Time period is the duration of one cycle in a repeating event, so the period is the reciprocal of the frequency.

That is, $T=\dfrac { 1 }{ f } \quad \quad or\quad \quad f=\dfrac { 1 }{ T } $

Multiple choice physics world of sounds characteristics of sound wave time period, frequency and amplitude of sound sound waves are longitudinal waves

The voices of Men, Women and children differ because of difference in their

  1. Lungs

  2. Wind pipr

  3. Vocal chords

  4. Larynx
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Lungs are used to filter the oxygen from air .

Wind pipe provides a path for air to go inside the lungs .
Larynx is responsible for the production of sound .
Vocal cords are inside the larynx , and their thickness decides the frequency of sound (shrill or grave ) , by which we can differentiate between the voices of a man (grave) , women and children(shrill) .

Multiple choice physics world of sounds characteristics of sound wave time period, frequency and amplitude of sound sound waves are longitudinal waves

When longitudinal wave propagates through a medium, then the physical quantities propagating in the direction of wave are

  1. Energy

  2. Energy, momentum and mass

  3. Energy and mass

  4. Energy and momentum
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

When a disturbance is produced in a medium , it is transported by oscillating particles of the medium , the disturbance is a kind of energy and carried by oscillating particles by passing it to the next particle , in this way a longitudinal wave propagates, therefore energy propagates in a longitudinal wave .

As there is no net movement of the medium particles in the propagation of wave , they just vibrate about the centers of rarefaction and compressions , therefore momentum is not transferred in a longitudinal wave . Thus only energy is propagating in the direction of wave. 

Multiple choice physics world of sounds characteristics of sound wave time period, frequency and amplitude of sound sound waves are longitudinal waves

If the velocity of sound in a gas is $200 {ms}^{-1}$ when the temperature is $127^0  C$, then the velocity of sound in the same gas when temperature is increased by $900^0  F$ is ______ ${ms}^{-1}$

  1. $200\sqrt{3}$

  2. 300
  3. $100\sqrt{5}$

  4. 450
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Velocity of sound is proportional to the square root of absolute temperature (T). 127 C = 400 K. A 900 F increase is 500 C, so the new temperature is 127 + 500 = 627 C = 900 K. The ratio of velocities is sqrt(900/400) = 1.5. Thus, 200 * 1.5 = 300 m/s.

Multiple choice physics world of sounds characteristics of sound wave time period, frequency and amplitude of sound sound waves are longitudinal waves

A sound wave is a pressure wave; regions of high (compressions) and low pressure (rarefactions) are established as the result of the vibrations of the sound source. These compressions and rarefactions result because sound :

  1. is more dense than air and thus has more inertia, causing the bunching up of sound

  2. waves have a speed which is dependent only upon the properties of the medium

  3. is like all waves; it is able to bend into the regions of space behind obstacles

  4. is able to reflect off fixed ends and interfere with incident waves vibrates longitudinally; the longitudinal movement of air produces pressure fluctuations
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

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. Compressions are the regions of high density and rarefactions are regions of low density.

Multiple choice physics world of sounds characteristics of sound wave time period, frequency and amplitude of sound sound waves are longitudinal waves

The speed of highly penetrating ultrasonic waves is :

  1. Lower than those of audible sound waves

  2. Higher than those of audible sound wave

  3. Much higher than those of audible sound waves

  4. Same as those of audible sound waves
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Speed of highly penetrating ultrasonic waves is greater than 20,000Hz equal to $10^7$Hz

Multiple choice physics world of sounds characteristics of sound wave time period, frequency and amplitude of sound sound waves are longitudinal waves

Suppose a stick is struck against a frying pan in vacuum. Which of the following is/are true?

  1. the frying pan vibrate

  2. we be able to hear the sound

  3. we can hear the sound just for few minutes

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Sounds are made by vibrations. Some vibrations are easy to see.
In this case, a stick is struck against a frying pan in vacuum. The frying pan vibrates. But this happens in vacuum. Sound waves require a medium to travel through. Outer space is a vacuum, and therefore it is not heard.
Hence, the sound created by the stick and frying pan is not heard.

Multiple choice physics world of sounds characteristics of sound wave time period, frequency and amplitude of sound sound waves are longitudinal waves

The velocity of sound in air is not affected by change in 

  1. the moisture content of the air.

  2. the temperature of air.

  3. the atmospheric pressure.

  4. the composition of air.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The speed of sound depends on temperature. The formula relating speed of sound and temperature is as follows:

$v = 331 + 0.6 \times T$, where $T$ is temperature in absolute scale and $v$ is in $m/s$.
Humidity has little effect on the speed of sound.
Air pressure has no effect at all in an ideal gas approximation. This is because pressure and density both contribute to sound velocity equally, and in an ideal gas the two effects cancel out each other, leaving only the effect of temperature.
Composition of air has also almost no effect on the speed of sound.