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Which is not condition for hearing sound?
1. There must be a vibrating body capable of transferring energy.
2. There must be a material medium to pick up and propagate energy.
3. The medium must have a large density.
4. There must be receiver to receive the energy and interpret it.

An instrument commonly used in a laboratory to produce a sound of some particular frequency is
1. sonar
2. electric bell
3. tuning fork
4. a stretched wire 

When a sound wave travels in air, the physical, quantity which is transferred from one place to the other is
1. mass
2. force
3. momentum
4. energy

In case pf longitudinal waves, the particles of medium vibrate
1. in th edirection of wave propagation
2. opposite to the direction of wave propagation
3. at right angles to the direction of wave propagation
4. none of the above

In case of transeverse waves the particles of a medium vibrate
1. in the direction of wave propagation
2. opposite to the direction of wave propagation
3. at the right angles to the direction wave propagation
4. none of the above

In the region of compressions or rarefaction, in a longitudinal wave the physical quantity which doest not change is
1. pressure
2. mass
3. density
4. volume
 

A slinky can produce in laboratory
1. transverse waves only
2. longitudinal waves only
3. both (1) and (2)
4. none of the above

The chnage in density/pressure of a medium from maximum value to minimum value, due to the propagation of a longitudinal wave is called a complete
1. oscillation
2. frequency
3. amplitude
4. none of these

If the frequency of wave is 25 Hz, the total number of compressions and rarefactions passing through a point in 1 second is
1. 25
2. 50
3. 100 
4. none of these

A stretched slinky is given a sharp push along its length. A wave travels from one end to another. The wave so produced is
1. transverse wave
2. longitudinal wave
3. stationary wave
4. none of the above

The sound waves having a frequency more than 20,000 Hz are called
1. infrasonic waves
2. supersonic waves
3. ultrasonic waves
4. hypersonic waves

Calculate the wavelength of radio waves of frequency ${10}^{°}$ Hz. The speed of radio waves is $3\times {10}^8 \mathrm{m} {\mathrm{s}}^{-1}$
1. 60 cm
2. 40 cm
3. 30 cm
4. 10 cm

A wave source produces 20 crests and 20 troughs in 0.2 sec. Find the frequency of the wave.
1. 200 Hz
2. 500 Hz
3. 100 Hz
4. 300 Hz

If the density of air at a point through which a sound wave is passing is maximum at an instant, the pressure at that point will be
1. minimum
2. same as the density of air
3. equal to the atmospheric
4. maximum

An object moving at a speed greater than that of sound is said to be moving at 
1. ultrasonic speed
2. sonic speed
3. infrasonic speed
4. supersonic speed

In which of the three media; air, water and steel, does sound travel the fastest?
1. air
2. water
3. steel 
4. none of these

An object is 11 km below sea level. A research vessel sends down a sonar signal to confirm this depth. After how long can it expect to get the echo? (Take the speed of sound in sea water as, $1, 520 \mathrm{m} {\mathrm{s}}^{-1}$.)
1. 15.30 s
2. 14.47 s
3. 12.20 s
4. 11.13 s

Which of the following is an elastic wave
1. Sound waves
2. light waves
3. X-rays
4. Radio waves

A big explosion on the moon canot be heard on the earth because
1. the explosion produces high frequency sound waves which are in audible
2. sound waves require a material medium for propagation
3. sound waves are absorbed in the moon's atmosphere
4. sound waves are absorbed in the earth's atmosphere

A persone is listening to a tone of 500 Hz, sitting at a distance of 450 m from the source of sound. The time interval between successive compressions from the source is
1. 0.2 s
2. 0.02 s
3. 0.002 s
4. 2.0 s

An echo is returned in 3 s. If the speed of sound is $342 \mathrm{m} {\mathrm{s}}^{-1}$, then the distance between the source of sound and the reflecting body is
1. 351 m
2. 513 m
3. 153 m
4. none of these

A submarine emits a sonar pulse, which returns fron under water cliff in 1.02 s. If the speed of sound in water is $1531 \mathrm{m} {\mathrm{s}}^{-1}$, the submarine is at a distance of
1. 780.8 m form cliff
2. 718.8 m from cliff
3. 714.8 m from cliff
4. none of these

A person can hear a sound of maximum frequency 20,000 Hz. If the speed of sound in air is $344 \mathrm{m} {\mathrm{s}}^{-1}$, the wavelength is
1. 0.176 m
2. 0.178 m
3. 0.0172 m
4. 0.0176 m

A boy stands 66.4 m in front of a high wall and then blows a whistle. If speed of sound is $332 \mathrm{m} {\mathrm{s}}^{-1}$, the echo is heard after
1. 0.45 s
2. 0.48 s
3. 0.40 s
4. 0.46 s

A boat at anchor is rocked by the waves, such that the distance between two consecutive crests is 100 m. If the wave velocity is $20 \mathrm{m} {\mathrm{s}}^{-1}$, th frequency of rocking boat is
1. 2 Hz
2. 1 Hz
3. 0.5 Hz
4. 0.2 Hz

Human ear cannot hear those mechanical waves whose frequency lies in the frequency range
1. less than 100 Hz but greater than 10000 Hz
2. between 1000 Hz and 5000 Hz
3. between 500 Hz and 20000 Hz
4. less than 20 Hz and more than 20000 Hz

Which one of the following properties of sound is affected by change in the air temperature?
1. frequency
2. amplitude
3. intensity
4. wavelength

A gun is fired in the air at a distance of 660 m from a person. He hears the sound of the gun after 2 s. What is the speed of sound?
1. 330 m ${\mathrm{s}}^{-1}$
2. 360 m ${\mathrm{s}}^{-1}$
3. 370 m ${\mathrm{s}}^{-1}$
4. 390 m ${\mathrm{s}}^{-1}$

A child hears an echo from a cliff 4 seconds after the sound from a powerful cracker is produced. How far away is the cliff from the child? Velocity of sound in air at ${20}^{°} \mathrm{C}$ is $344 \mathrm{m} {\mathrm{s}}^{-1}$.
1. 688 m
2. 672 m
3. 660 m
4. 650 m

A ship send on a high frequency sound wave and receives an echo after 1 second. What is the depth of the sea? Speed of sound in water is 1500 m/s.
1. 700 m
2. 750 m
3. 800 m
4. 850 m

A boy sitting on a boat fires a gun. An onserver P is at a distance of 50 m from the boat. Another observer Q is a driver, who is 50 m under water. Both hear the sound of gun, then
1. P hears the sound first
2. Q hears the sound first
3. Both P and Q hear the sound at the same time
4. none of the above

A wave pulse moving through air causes change in the ensity of the air. The variation of density at two different instant are shown in the figure. The figure (a) corresponds to, t=10 s and figure (b) to t=10.5 s
 
 
The speed of the wave pulse is
1. 520 m ${\mathrm{s}}^{-1}$
2. 320 m ${\mathrm{s}}^{-1}$
3. 300 m ${\mathrm{s}}^{-1}$
4. 220 m ${\mathrm{s}}^{-1}$

A sound wave has a frequency of 1000 Hz and a wave length of 34 cm. How long will it take to travel 1 km?
1. 3.20 s
2. 2.94 s
3. 5.94 s
4. 3.10 s
 

Two waves of sinusoidal waveforms have different wavelengths and different amplitude. They will be having
1. same pitch and different intensity
2. same quality and different quality
3. different quality and different intensity
4. same quality and same pitch
 

A source of sound of frequency 600 Hz is placed inside water. The speed of sound in water is 1500 m ${\mathrm{s}}^{-1}$ and in air is 300 m ${\mathrm{s}}^{-1}$. The frequency of sound recorded by an observer who is standing in air is
1. 200 Hz
2. 300 Hz
3. 120 Hz
4. 600 Hz

Each of the properties of sound listed in column. A primarily depends on one of the quantities in column B. Choose the matching pairs from two columns.
 Column A                       Column B
Pitch                              Waveform
Quality                           Frequency
Loudness                        Intensity
1. Pitch-waveform, Quality-frequency, Loudness-intesity
2. Pitch-frequency, Quality-waveform, Loudness-intensity
3. Pitch-intensity, Qualitty-waveform, Loudness frequency
4. Pitch-waveform, Quality-iintensity, Loudness-frequency

A light pointer fixed to one prong to a tuning fork touches a vertical plate. The fork is set vibrating and the plate is allowed to fall freely. If eight oscillations are counted when the plate falls through 10 cm, the frequency of the tuning fork is
1. 360 Hz
2. 280 Hz
3. 560 Hz
4. 56 Hz

The highest frequency produced by a man is 1700 Hz and that of a woman is 2780 Hz. The ratio of wavelengths of sound of man and woman are (speed of sound is 340 m ${\mathrm{s}}^{-1}$)
1. 1:0.60
2. 1:0.61
3. 1:0.62
4. 1:0.59

The wavelength and frequency of a sound wave in medium A is 20 cm and 1650 Hz. Keeping the medium same, if wavelength is changed to 16 cm, then new frequency is
1. 2060 Hz
2. 2062.5 Hz
3. 2061 Hz
4. 2063.0 Hz

A man stands between two cliffs and fires a gun. He hears two successive echoes after 3 s and 5 s. The distance between two cliffs is
1. 1310 m
2. 1320 m
3. 1315 m
4. 1312 m

Water waves are
1. longitudinal
2. transverse
3. both longitudinal and transverse
4. neither longitudinal nor transverse

An echo repeats two syllables. If the velocity of sound is 330 m ${\mathrm{s}}^{-1}$, thenthe distance of the reflecting surface is
1. 66.0 m
2. 33.0 m
3. 99.0 m
4. 16.5 m

A plane wave of sound travelling in air is incident upon a plane water surface. The angle of incidence is ${30}^{°}$. If the velocity of sound in water 1400 m ${\mathrm{s}}^{-1}$, and the velocity of sound in air is 330 m ${\mathrm{s}}^{-1}$, there will be
1. Reflection only
2. Refraction only
3. both reflection and refraction
4. neither reflection and refraction

If you go on increasing the stretching force on a wire in a guitar, uts frequency
1. increases
2. decreases
3. remains unchanged
4. none of the above

A pendulum vibrates with a time period of 1 second. The sound produced by it is
1. supersonic
2. audible
3. infrasonic
4. ultrasonic

Flash and thunder are produced simultaneously. But thunder is heard a few seconds after the flash is seen. This is because
1. speed of sound is greater than speed of light
2. speed of sound is equal to the speed of light
3. speed of light is much greater than the speed of sound
4. none of these

During night, distant sounds such as that of the traffic and the loudspeakers become louder than during day. This is due to
1. reflection of sound wave 
2. refraction of sound wave
3. absence of other sounds
4. clear perception of hearing

A longitudinal wave is produced on a toy slinky. The wave travels at a speed of 30 cm ${\mathrm{s}}^{-1}$ and the frequency of the wave os 20 Hz. What is the minimum seperation between the consecutive compressions of the slinky?
1. 1.0 cm
2. 1.5 cm
3. 2.5 cm 
4. 3.0 cm 

Sound travels at a speed of 334 m ${\mathrm{s}}^{-1}$ in the air. This means that
1. the source of sound moves 334 m in one second
2. the listener moves 334 m in one second
3. air moves 334 m in one second
4. the disturbance in air moves 334 m in one second

Non-mechanical wave can travel
1. in vacuum as well as in a medium
2. in vacuum but not in a medium
3. in medium but not in a vacuum
4. neither in a medium nor in vacuum