Waves of Sound

Q.

A man is standing between two parallel cliffs and fires a gun. If he hears first and second echoes after $1.5s$ and $3.5s$ respectively, the distance between the cliffs is (Velocity of sound in air = $340m{s}^{-1}$)

1. 1190 m

2. 850 m

3. 595 m

4. 510 m

Q. When two sound waves with a phase difference of $\frac{\pi }{2},$ and each having amplitude A and frequency $\omega$, are superimposed on each other, then the amplitude and frequency of resultant wave is

1. 
2. 
3. 
4. 

Q.

A listener moves towards stationary sound source with a constant speed and crosses it then the correct graph between Apparent frequency with time is please explain

Q.

Where does maximum constructive interference occur?

Q.

A stone is dropped from a 500 m tall building into a pond. When is sound of splash heard after the dropping of the stone? g = 10 $m/s^2$, speed of sound = 340 m/s

1. 10 s

2. 1.47 s

3. 11.47 s

4. immediately (at t = 0)

Q.

The speed of a wave is $340m{s}^{-1}$. What is the wavelength of the wave if its frequency is 500 Hz?

1. 0.68 m

2. 6.8 m

3. 68 m

4. 0.68 cm

Q. When sound wave is refracted from air to water, which of the following will remain unchanged?

1. Wave number

2. Wavelength

3. Wavevelocity

4. Frequency

Q. A stone is dropped from the top of a tower of $500\text{m}$ height, into a pond of water at the base of the tower. When is the splash heard at the top?

$(\text{Given}g=10{\text{ms}}^{-2}$ and speed of sound $=340{\text{ms}}^{-1})$

1. $10\text{s}$
2. $11.47\text{s}$
3. $1.10\text{s}$
4. $20\text{s}$

Q. A block of mass $1\text{kg}$ attached to a spring is made to oscillate with an initial amplitude of $12\text{cm}$. After $2$ minutes the amplitude decreases to $6\text{cm}$. Determine the value of the damping constant for this motion. (take $ln2=0.693$).

1. $0.69\times {10}^2{\text{kg s}}^{-1}$
2. $3.3\times {10}^2{\text{kg s}}^{-1}$
3. $5.7\times {10}^{-3}{\text{kg s}}^{-1}$
4. $1.16\times {10}^{-2}{\text{kg s}}^{-1}$

Q. A road runs midway between two parallel rows of buildings. A motorist moving with a speed of $36km/hour$ sounds the horn. He hears the echo one second after he has sounded the horn. The distance between the $2$ rows of buildings is (Velocity of sound is $330m/s$)

1. $300m$
2. $150m$
3. $1080m$
4. $330m$

Q.

A man is standing in a valley between two parallel mountains. He fires a gun and hears echo at an interval of 2s and 3.5s. what is the distance between 2 mountains? (Take speed of sound = 350 m/s)

1. 350 m

2. 700 m

3. 612.5 m

4. 962.5 m

Q.

An organ pipe $P_1$ closed at one end and vibrating in its first overtone pipe $P_2$ open at both ends vibrating in its third overtone are in resonance with a given tuning fork. The ratio of the lengths of $P_1$ to that of $P_2$ is?

Q. If the medium changes, for the same wave the frequency remain the same but the speed changes because the wave speed apart of frequency also depends upon:

1. Frequency
2. Wavelength
3. Amplitude
4. All of them

Q. A man is standing between two parallel cliffs and fires a gun. If he hears first and second echoes after 1.5 s and 3.5 s respectively, the distance between the cliffs is (Velocity of sound in air = $340m{s}^{-1}$)

1. 1190 m
2. 850 m
3. 595 m
4. 510 m

Q. A sound wave of frequency 100 Hz is travelling in air. The speed of sound in air is 350 m s${}^{-1}$. By how much is the phase changed at a given point in 2.5 ms?

1. 

2. 

3. 

4. 

Q. A man is standing between two parallel cliffs and fires a gun. If he hears the echoes after 1.5s and 3.5s respectively, the distance between the cliffs is (velocity of sound in air = 340m/s)

1. 1190m
2. 850m
3. 595m
4. 510m

Q. A wave passes from one minimum to another medium. Mention the property of the wave
which changes
which does not change.

Q.

If in a medium wave's wavelength is decreased, what will happen to its frequency?

1. Decrease

2. Increase

3. Data insufficient need density too

4. Frequency Doesn't depend on wavelength

Q.

A man is standing in a valley between two parallel mountains. He fires a gun and hears echo at an interval of 2s and 3.5s. what is the distance between 2 mountains? (Take speed of sound = 350 m/s)

1. 350 m

2. 700 m

3. 962.5 m

4. 612.5 m

Q. A person places his ear at the end of a long steel pipe. He hears two distinct sounds at an interval of 0.5 s when another person hammers at the other end of the pipe. If the speed of the sound in metal and air are 3630 m$s^{-1}$ and 330 m$s^{-1}$ respectively, then the distance between the two persons is

1. 90.75 m
2. 181.5 m
3. 363 m
4. 1650 m

Q. A stone is dropped into a lake from a tower 500m high. The sound of the splash will be heard by a man on the tower after a time of (velocity of sound in air=350 m/s)

1. $21s$
2. $10s$
3. $11.4s$
4. $1s$

Q. The splash is heard after $2.05s$ after the stone is dropped into a well of depth $19.6$m the velocity of sound is:

1. $342m{s}^{-1}$
2. $372m{s}^{-1}$
3. $392m{s}^{-1}$
4. ${352}^{-1}$

Q.

A stone is dropped into a lake from a tower 500 metre high. Taking the speed of sound as 330 m/s, the sound of the splash will be heard by the man approximately after

1. 11.5 seconds

2. 21 seconds

3. 10 seconds

4. 14 seconds

Q.

A stone is dropped into a lake from a tower 500 metre high. Taking the speed of sound as 330 m/s, the sound of the splash will be heard by the man approximately after

1. 11.5 seconds

2. 10 seconds

3. 14 seconds

4. 21 seconds

Q. Sound waves can diffract easily because

1. Their wavelength is very small
2. Their wavelength is large
3. It can refract
4. It can reflect

Q.

If in a medium wave's wavelength is decreased, what will happen to its frequency?

1. Increase

2. Decrease

3. Frequency Doesn't depend on wavelength

4. Data insufficient need density too

Q. A man is driving a car at a speed of 72 kmph towards a hill. He sounds the horn and hears its echo after 2 seconds. At what distance from the hill the horn was sounded. (Velocity of sound = 340 m/s)

1. 420 m
2. 390 m
3. 340 m
4. 260 m

Q. A source of the sound of frequency $90$ vibrations/sec is approaching a stationary observer with a speed equal to $1/10$ the speed of sound. What will be the frequency heard by the observer

1. $80vibrations/sec$
2. $120vibrations/sec$
3. $90vibrations/sec$
4. $100vibrations/sec$

Q. When sound wave is refracted from air to water, which of the following will remain unchanged?
(a) Wave number
(b) Wavelength
(c) Wave velocity
(d) Frequency

Q.

A stone is dropped from a 500 m tall building into a pond. When is sound of splash heard after the dropping of the stone? g = 10 $m/s^2$, speed of sound = 340 m/s

1. 10 s

2. 1.47 s

3. 11.47 s

4. immediately (at t = 0)