Characteristics of Sound Waves

Q.

The frequency of a source of sound is $100\mathrm{Hz}$. How many times does it vibrate in a minute?

Q.

Which type of sound waves are produced due to an earthquake before the main shock wave begins?

1. None of the above

2. Ultrasonic

3. Infrasonic

4. Audible sound

Q.

Which of the following sound wave has the highest pitch?

1. 

2. 

3. 

4. 

Q.

Write any three difference between musical sound and noise.

Q.

The amplitude of forced vibrations is generally ________ than the amplitude of applied external force.

1. More

2. Less

3. Equal to

4. None of these

Q.

The loudness of sound is measured in Hz.

1. True
2. False

Q.

The pitch of a sound produced by a flute _________ by closing holes.

Q.

An observer stands at a certain distance away from a cliff and produces a loud sound. He hears the echo of the sound after $1.8s.$ Calculate the distance between the cliff and the observer if the velocity of sound in air is $340m{s}^{-1}$.

Q.

An echo is heard by a radar in $0.08\mathrm{s}$. If velocity of radio waves is $3\times {10}^8{\mathrm{ms}}^{-1}$, how far is the enemy plane?

Q.

Sometimes when a vehicle is driven at a particular speed, a rattling sound is heard. Explain briefly, why this happens and gives the name of the phenomenon taking place.

Q.

List one source of noise in: Homes

Q.

The displacement-distance graph for a particle in a wave is shown below.
If $2\lambda +R=3A$ then find the value of R.
$\lambda$= wavelength of wave,
A = amplitude of wave

Q.

The sound of a bird is more__________ than that of a lion.

Q.

Difference between the following high pitch and low pitch.

Q.

A vibrating tuning fork is placed over the mouth of a burette filled with water. The tap of the burette is opened and the water level gradually starts falling. it is found that the sound from the tuning fork becomes very loud for a particular length of the water column.

Name the phenomenon taking place when this happens.

Q.

Choose the correct option:

$\begin{array}{cccc}1.& \text{Tone}& i.& \text{frequencies that are integral multiple of fundamental frequency.}\\ 2.& \text{Note}& ii.& \text{sound of single frequency.}\\ 3.& \text{Overtone}& iii.& \text{sound of multiple frequencies.}\\ 4.& \text{Harmonic}& iv.& \text{higher frequencies other than fundamental frequency.}\end{array}$

1. 1 - ii, 2 - iii, 3 - i, 4 - iv

2. 1 - iii, 2 - ii, 3 - iv, 4 - i

3. 1 - ii, 2 - iv, 3 - iii, 4 - i

4. 1 - ii, 2 - iii, 3 - iv, 4 - i.

Q.

Sounds of frequency less than 20 Hz are called

1. supersonic sounds

2. ultrasonic sounds

3. sonic sounds

4. infrasonic sounds

Q. What is the S.I. unit of wavelength?

1. decibel
2. metre
3. second
4. pascal

Q.

Define sound andwrite the type of sound waves with advantage and disadvantages(250)words.

Q.

When we change feeble sound to loud sound, we increase its:

1. Velocity
2. Amplitude
3. Frequency
4. Wavelength

Q. In a gaseous medium, a sound wave is ___.

1. (a) and (b) above.
2. longitudinal
3. transverse
4. non-mechanical

Q.

In a sound wave, compression is the region of the low pressure.

1. True

2. False

Q.

A wave source produces $20$ crests and $20$ troughs in $0.2sec$. Find the frequency of the wave.

1. $500Hz$

2. $100Hz$

3. $300Hz$

4. $200Hz$

Q.

Why is the loud sound heard at acoustic resonance?

Q. it is observed that during march past we hear a bass drum distinctly from a distance compared to side drums name the characterisitics of sound associated with the above observation

Q. If a longitudinal wave travels from East to West, then the particles of air move in:

1. North-South
2. East-West
3. North-West
4. South-East

Q.

The unit of the quantity on which pitch of the sound depends:

1. Hertz
2. second
3. metre/second
4. metre

Q.

In a sound wave, compression is the region of the low pressure.

1. True

2. False

Q. If a longitudinal wave travels from East to West, then the particles of air move in:

1. South-East
2. East-West
3. North-West
4. North-South

Q.

A key of a mechanical piano is struck gently. The same key is then struck again, but much harder this time. In the second case:

1. The sound detected will be louder and its pitch remains the same.

2. The loudness of the sound detected remains the same but its pitch will be higher.

3. Both the loudness of the sound detected and its pitch will remain unaffected.

4. The sound detected will be louder and its pitch will be higher.