Can sound travel through (a) iron, and (b) water?

Can sound travel through vacuum?

Name the type of waves which are used by astronauts to communicate with one another on moon (or in outer spece).

Name one solid, one liquid and one gas through which sound can travel.

Which of the following cannot transmit sound?

Water, Vacuum, Aluminium, Oxygen gas

Name the physical quantity whose SI unit is ‘hertz’.

What is the SI unit of frequency?

What type of wave is represented :

(a) by density-distance graph?

(b) by displacement-distance graph?

Is the speed of sound more in water or in steel?

In which medium sound travels faster: air or iron?

In which medium sound travels fastest: air, water or steel?

Out of solids, liquids and gases :

(a) in which medium sound travels slowest?

(b) in which medium sound travels fastest?

Which of the following is the speed of sound in copper and which in aluminium?

(a) 5100 m/s (b) 1500 m/s

(c) 3750 m/s

If you want to hear a train approaching from far away, why is it more convenient to put the ear to the track?

What is the speed of sound :

(a) in air?

(b) in water?

(c) in iron?

What name is given to those aircrafts which fly at speeds greater than the speed of sound?

A jet aircraft flies at a speed of 410 m/s. What is this speed known as?

What is meantby supersonic speed?

State one observation from everyday life which shows that sound travels much more slow than light.

Name the two types of waves which can be generated in a long flexible spring (or slinky).

A stone is dropped on the surface of water in a pond. Name the type of waves produced.

Name the type of wave produced when a tuning fork is struck in air.

What is the general name of the waves consisting of :

(a) compressions and rarefactions?

(b) crests and troughs?

State the general name of the waves on which the particles of the medium vibrate:

(i) in the same direction as wave.

(ii) at right angles to the direction of wave.

What type of waves are illustrated by the movement of a rope whose one end is fixed to a pole and the other end is moved up and down?

What should an object do to produce sound?

What is the name of the strings which vibrate in our voice box when we talk?

Name the device which is used to produce sound in laboratory experiments.

What is the nature of sound waves in air?

What conclusion can be obtained from the observation that when the prongs of a sound making tuning fork touch the surface of water in a beaker, the water gets splashed?

State whether the following statement is true or false:

Sound produced by a vibrating body travels to our ears by the actual movement of air.

Which of the following travels slowest in air and which one fastest?

Supersonic aircraft, Light, Sound

Which term is used to denote a speed greater than the speed of sound?

In which medium sound travels faster: air or hydrogen?

A tuning fork has a number 256 marked on it. What does this number signify?

What is the time-period of a tuninh fork whose frequency is 200 Hz?

Calculate the frequency of a wave whose time-period is 0.02 s.

What will be the change in the wavelength of a sound wave in air if its frequency is doubled?

If 20 waves are produced per second, what is the frequency in hertz?

Fill in the following blanks with suitable words

(a) Sound is caused by ………….

(b) A sound wave consists of places of higher pressure called ….. and places of …….. pressure called …………

(c) Wave speed in metres per second equals frequency in …………. Multiplied by ……….. in ………

(d) Sound cannot travel through ……….

(e) The speed of sound in a solid is ………… than the speed of sound in air.

(f) When the frequency of the sound is increased, the wavelength …………

What is vaccum? Explain why, sound cannot travel through vacuum?

Explain the term ‘amplitude’ of a wave. Draw the diagram of a wave and mark its amplitude on it.

Distinguish between longitudinal and transverse waves.

Are sound waves longitudinal or transverse?

A cricket ball is seen to hit the bat first and the sound of hitting is heard a little later. Why?

Explain why, the flash of lightning reaches us first and the sound of thunder is heard a little later.

Explain why, the flash of a gun shot reaches us before the sound of the gun shot.

Which of the following terms apply to sound waves in air and which to water waves?

Transverse, Rarefaction, Trough, Crest, Compression, Longitudinal

Name four ways in which sound can be produced.

Calculate the speed of a sound wave whose frequency is 2 kHz and wavelength 65 cm.

If a ringing bicycle bell is held tightly by hand, it stops producing sound. Why?

Which object is vibrating when the following sounds are produced?

(i) The sound of a sitar

(ii) The sound of table

(iii) The sound of a tuning fork

(iv) The buzzing of a bee or mosquito

(v) The sound of a flute

Give reason for the following :

In most of the cases, we cannot see the vibrations of a sound producing object with our eyes.

Describe a simple experiment to show that the prongs of a sound producing tuning fork are vibrating.

When we open a gas tap for a few seconds, the sound of escaping gas is heard first but the smell of gas comes later. Why?

A sound signal of 128 vibrations per second has a wavelength of 2.7 m. Calculate the speed with which the wave travels.

A wave is moving in air with a velocity of 340 m/s. Calculate the wavelength if its frequency is 512 vibrations/sec.

Define the ‘frequency’ and ‘time-period’ of a wave. What is the relation between the two?

Explain why, a ringing bell suspended in a vacuum chamber cannot be heard outside.

The frequency of the sound emitted by the lioudspeaker is 1020 Hz. Calculate the wavelength of the sound wave in air in cm where its velocity is 340 m/s.

What is the difference between a compression and a rarefaction in a sound wave? Illustrate your answer with a sketch.

What is sound? What type of waves are sound waves in air?

Describe an experiment to show that sound cannot pass through vacuum.

How is sound produced? Explain with the help of an example.

How does sound from a sound producing body travel through air to reach our ears? Illustrate your answer with the help of a labelled diagram.

An electric bell is suspended by thin wires in a glass vessel and set ringing. Describe and explain what happens if the air is gradually pumped out of the glass vessel.

Why cannot a sound heard on the moon? How do astronauts talk to one another on the surface of moon?

When we put our ear to a railway line, we can hear the sound of an approaching train even when the train is far off but its dound cannot be heard through the air. Why?

How could you convince a small child that when you speak, it is not necessary for air to travel from your mouth to the ear of a listener?

Define the terms ‘frequency’, ‘wavelength’ and ‘velocity’ of a sound wave. What is the relation between them?

A body vibrating with a time-period of s produces a sound wave which travels in air with a velocity of 350 m/s. Calculate the wavelength.

What are longitudinal waves and transverse waves? Explain with the help of labelled diagrams.

Give two examples each of longitudinal waves and transverse waves.

Explain the terms ‘compressions’ and ‘rarefactions’ of wave. What type of waves consist of compressions and rarefactions?

A worker lives at a distance of 1.32 km from the factory. If the speed of sound in air be 330 m/s, how much time will the sound of factory siren take to reach the worker?

Explain the terms ‘crests’ and ‘troughs’ of a wave? What type of waves consist of crests and troughs?

The flash of a gun is seen by a man 3 seconds before the sound is heard. Calculate the distance of the gun from the man (Speed of sound in air is 332 m/s).

Which of the following statement best describes frequency?

A. the maximum disturbance caused by a wave

B. the number of complete vibrations per second

C. the distance between one crest of a wave and the next one

D. the distance travelled by a wave per second

Which of the following vibrates when a musical note is produced by the cymbals in an orchestra?

A. stretched strings

B. stretched membranes

C. metal plates

D. air columns

If the speed of a wave is 340 m/s and its frequency is 1700 Hz, then l for this wave in cm will be:

A. 2 B. 0.2

C. 20 D. 200

A musical instrument is producing a continuous note. This note cannot be heard by a person having a normal hearing range. This note must then be passing through:

A. water B. wax

C. vacuum D. empty vessel

Which one of the following does not consist of transverse waves?

A. light emitted by a CFL

B. TV signals from a satellite

C. ripples on the surface of a pond

D. nusical notes of an orchestra

Sound travels in air :

A. if particles of medium travel from one place to another

B. if there is no moisture in the atmosphere

C. if disturbance moves

D. if both, particles as well as disturbance move from one place to another

In the sound wave produced by a vibrating turning fork shown in the diagram, half the wavelength is represented by: (picture)

A. AB B. BD

C. DE D. AE

The maximum speed of vibrations which produce audible sound will be in :

A. dry air B. sea water

C. ground glass D. human blood

The sound waves travel fastest:

A. in solids B. in liquids

C. in gases D. in vacuum

The speeds of sound in four different media are given below. Which of the following is the most likely speed in m/s with which the two under water whales in a sea talk to each other when separated by a large distance?

A. 340 B. 5170

C. 1280 D. 1530

When the pitch of note produced by a harmonium is lowered, then the wavelength of the note:

A. decreases

B. first decreases and then increases

C. increases

D. remains the same

The velocities of sound waves in four media P. Q, R and S are 18,000 km/h, 900 km/h, 0 km/h, and 1200 km/h respectively. Which medium could be a liquid substance?

A. P B. Q

C. R D. S

Which of the following can produce longitudinal waves as well as transverse waves under different conditions?

A. water B. TV transmitter

C. slinky D. tuning fork

Draw the sketches of two waves A and B that wave A has twice the wavelength and half the amplitude of wave B

A device called oscillator is used to send waves along a stretched string. The string is 20 cm long, and four complete waves fit along its length when the oscillator vibrates 30 times per second. For the waves on the string:

(a) what is their wavelength?

(b) what is their frequency?

(c) what is their speed?

Through which of the following materials can sound travel?

Wood, air, water, sream, ice, hydrogen, steel, diamond.

A sound producing body is at considerable distance from a man. There can be four different media W, X, Y and Z between the sound producing body and the man. The medium X brings the sound to man most quickly whereas medium Z tajes the maximum time. The time taken by medium W in bringing sound to man is less than that of X but more than that of Z. The medium Y, however, fails to bring the sound from the sound producing body to the man. Which medium could be the one:

(a) having no fixed shape and no fixed volume?

(b) having a fixed volume but no fixed shape?

(c) having the same composition as that on the moon?

(d) having a fixed shape and a fixed volume?

The longitudinal waves travel in a coiled spring at a rate of 4 m/s. The distance between two consecutive compressions is 20 cm. Find:

(i) Wavelength of the wave

(ii) Frequency of the wave

Which property of sound leads of the formation of echoes?

What name is given to the repetition of sound caused by the reflection of sound waves?

What name is given to the persistence of sound in a big hall or auditorium?

Name three devices which work on the reflection of sound.

What is the other name of a loud-hailer?

Name the three characteristic of sound.

Name the unit used to measure the loudness of sound. Also write its symbol.

Name the characteristic which helps us distinguish between a man’s voice and woman’s voice, even without seeing them.

How does the pitch of a sound depend on frequency?

Name the characteristic of sound which depends on

(a) amplitude

(b) frequency, and

(c) waveform.

Name the characteristic of sound which can distinguish between the ‘notes’ (musical sounds) played on a flute and a sitar (both the notes having the same pitch and loudness).

Name the organs of hearing in our body.

Name that part of ear which vibrates when outside sound falls on it.

Name the three tiny bones present in the middle part of ear.

There are three small bones in the middle ear—anvil, hammer and stirrup:

(a) Which of these bones is in touch with ear-drum?

(b) Which of these bones is in touch with oval window?

What is the function of three tiny bones in the ear?

Name the tube which connects the middle ear to throat.

Name the nerve which carries electrical impulses from the cochlea of ear to the brain.

What is the name of passage in outer ear which carries sound waves to the ear-drum?

Why should we not put a pin or pencil in our ears?

What type of scans are used these days to monitor the growth of developing baby in the uterus of the mother?

How is an ultrasound scan for fetus (unborn baby) better than aX-ray?

What is the name if the device which is used to find the depth of sea (or ocean) by using ultrasonic sound waves?

Write the full name of ‘SONAR’.

Name the principle on which a soundboard works.

Name the device which is used to address a small gathering of people.

Name the device used by doctors to listen to our heartbeats.

What is the shape of a soundboard kept behind the speaker on the stage of a big hall?

Name two sound absorbing materials (or obhects) which can make our big room less echoey.

Can we hear

(a) infrasonic waves

(b) ultrasonic waves?

What name is given to the sound waves of frequency too low for humans to hear?

What name is given to the sound waves of frequency too high for humans to hear?

What type of sound waves are produced by a vibrating simple pendulum?

What happens to the loudness of a sound if its amplitude decreases?

What happens to the loudness of a sound if its amplitude decreases?

What name is given to sound waves of frequencies higher than 20 kHz?

Fill in the following blanks with suitable words:

(a) An echo is simply a ………. Sound.

(b) Pitch od sound depends on ………

(c) Loudness of sound depends on ……….

(d) Quality of sound depends on ……….

(e) Echoes are caused by the …………of sound.

On which day, a hot day or a cold day, an echo is heard sooner? (Give reason for your answer.

In which medium, air or water, an echo is heard much sooner? Why?

What is reverberation? What will happen if the reverberation time in a big hall is too long?

How can reverberations in a big hall or auditotium be reduced?

Why do we hear more clearly in a room with curtains then a room withour curtains?

What is a megaphone? Name the principle on which a megaphone works.

What is a bulb horn? Name the principle on which a bulb horn works.

What is a stethoscope? Name the principle on which a stethoscope works.

What is a soundboard? Explain the working of a soundboard with the help of a labelled diagram.

What is meant by the ‘loudness’ of sound? On what factor does the loudness of a soind depend?

Draw labelled diagrams to represent (a) soft sound, and (b) loud sound, of the same frequency.

Explain the term ‘pitch’ of a sound. On what factor does the ‘pitch’ of a sound depend?

Draw labelled diagrams to represent sound of (a) low pitch, and (b) high pitch, of the same loudness.

What is meant by the quality (or timbre) of sound? On what factor does the quality (or timbre) of a sound depend?

Explain why, if we strike a table lightly, we hear a soft sound but if we hit the table hard, a loud sound is heard.

Give one use of ultrasound in industry and one in hospitals.

How is it that bats are able to fly at night without colliding with other objects?

Explain how, bats use ultrasound to catch the prey.

Explain how, flaws (or defects) in a metal block can be detected by using ultrasound.

Why are the ceilings of concert halls made curved? Draw a labelled diagram to illustrate your answer.

Draw a labelled diagram to show the multiple reflections of sound in apart of the stethoscope tube.

What is the range of frequencies associated with

(a) infrasound

(b) audible sound, and range of the frequeny

What is the difference between infrasonic waves and ultrasonic waves?

Choose the infrasonic waves and ultrasonic waves from the following frequencies:

(i) 10,000 Hz (ii) 30,000 Hz

(iii) 18 Hz (iv) 50,000 Hz

(v) 10 Hz

What is the frequency range of hearing in humans?

Which of the following sound frequencies cannot be heard by a human ear?

(i) 10 Hz (ii) 100 Hz

(iii) 10,000 Hz (iv) 15 Hz

(v) 40,000 Hz

The echo of a sound is heard after 5 seconds. If the speed of sound in air be 343 m/s, calculate the distance of the reflecting surface.

The speed of sound in water is 1500 metres per second. How far away from an under-sea rock should a deep sea diver be so that he can hear his own echo?

What is meant by ‘reflection of sound’? What type of surface are the best reflecting sound?

Name any two objects which are good reflectors of sound.

State the laws of reflection of sound.

What is an echo? How is echo formed?

What is the minimum distance in air required from a sound reflecting surface to hear an echo (at 20°C)?

A man standing 825 metres away from a cliff (steep rock) fires a gun. After how long will he hear its echo? Speed of sound in air is 33 m/s.

What is ultrasound? What is the difference between ordinary sound and ultrasound?

Write any three applications (or use) of ultrasound.

What are infrasonic waves? Name two animals which produce infrasonic waves.

What are infrasonic waves? Name two animals which can produce ultrasonic waves.

The audible range of frequencies of an average human ear is from 20 Hz to 20 kHz. Calculate the corresponding wavelengths. (Speed of sound in air is 344 m s^-1).

Define the following terms:

(1) Echolocation

(2) Echocardiography, and

(3) Ultrasonography.

Name an animal which navigates and find food by echolocation.

Which of the two produces ultrasonic waves: porpoise or whale?

What is sonar? Explain its use.

A sonar station picks up a return signal after 3 seconds. How far away is the object? (Speed of sound in water = 1440 m/s).

Draw a neat and labelled diagram of the human ear. With the help of this diagram, explain the construction and working of the human ear.

In SONAR we use:

A. ultrasonic waves

B. infrasonic waves

C. radio waves

D. audible sound waves

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

A. frequency B. amplitude

C. velocity D. wave length

Which kind of sound is produced in an earthquake before the main shock wave begins?

A. ultrasound B. infrasound

C. audible sound

D. none of the above

Before playing the orchestra in a musical concert, a sitarist tries to adjust the tension and pluck the strings suitably. By doing so he is adjusting:

A. intensity of sound only

B. amplitude of sound only

C. frequency of the sitar string with the frequency of other musical instruments

D. loudness of sound

‘Note’ os a sound:

A. of a mixture of several frequencies

B. of mixture of only two frequencies

C. of a single frequency

D. always unpleasant to listen to

A key of mechanical piano is first struck gently and then struck again but much harder this time. In the second case:

A. sound will be louder but pitch will not be different

B. sound will be louder and the pitch will also be higher

C. sound will be luder but pitch will be lower

D. both loudness and pitch will remain unaffected

one of the following can hear infrasound. This one is :

A. dog B. bat

C. rhinoceros D. humans

An echo-sounder in a trawler (fishing boat) receives an echo from a shoal of fish 0.4 s after it was sent. If the speed of sound in water is 1500 m/s, how deep is the shoal?

A. 150 m B. 300 m

C. 600 m D. 7500 m

The speed of highly penetrating ultrasonic waves is:

A. lower than those of audible sound waves

B. higher than those of audible sound waves

C. much higher than those of audible sound waves

D. same as those of audible sound waves

The ultrasound waves can penetrate into matter to a large extent because they have :

A. very high speed

B. very high frequency

C. very high wavelength

D. very high amplitude

The frequencies of four sound waves are given below. Which of these sound waves can be used to measure the depth of sea by the echo method?

A. 15,000 Hz B. 10 kHz

C. 50 kHz D. 10,000 Hz

Which of the following frequency of sound can be generated by a vibrating simple pendulum as well as by the vibrating vocal cords of a rhinoceros?

A. 5 kHz B. 25 Hz

C. 10 Hz D. 15,000 Hz

Which of the following device does not work on the multiple reflections of sound waves?

A. stethoscope B. hydrophone

C. soundboard D. megaphone

What type of waves are generated by SONAR device fixed to a fishing ship?

A. water waves B. radio waves

C. sound wavesD. infrared waves

We can distinguish between the musical sounds produced by different singers on the basis of the characteristic of sound called:

A. frequency B. timbre

C. pitch D. loudness

At 20°C, the minimum distance of a person from a sound reflecting surface to hear an echo is :

A. 12.2 m B. 17.2 m

C. 15.2 m D. 34.4 m

The drawing shoes a ship 800 m from a cliff. A gun is fired on the ship. After 5 seconds the people at the front of the ship hear the sound of the gun again.

(a) What is the name of this effect?

(b) What happens to the sound at the cliff?

(c) How far foes the sound travel in 5 seconds?

(d) Calculate the speed of sound.

Consider the following sound waves marked A, B, C and D:

(a) Which two waves represent sounds of the same loudness but different pitch?

(b) Which two waves represent sounds of the same frequency but different loudness?

(c) State whether all these sound waves have been produced by the same vibrating body or different vibrating bodies?

(d) Which vibrating body/bodies could have generated the sound waves shown here?

In an experiment, Anhad studies sound waves. He sets up a loudspeaker to produce sound as shown below:

Picture

Anhad adjusts the signal to the loudspeaker to give a sound of frequency 200 Hz.

(a) What happens to the air in-between Anhas and the loudspeaker?

(b) Explain how Anhad receives sound in both ears.

Figure X showa a trace of a sound wave produced by a particular tuning fork:

Picture

(a) On the graph paper given in Figure Y, draw a trace of the sound wave which has higher frequency than that shown in Figure X.

(b) On the graph paper shoen in Figure Z, draw a trace of the sound wave which has a larger amplitude than that shown in Figure X.

Three different vibrating objects produce three types of sounds X, Y and Z. Sounds X and Y cannot be heard by a man having normal range of hearing but sound Z can be heard easily. The sound X is used in hospitals to break kidney stones of a patient into fine grains whioch then get flushed out with urine. The sound Y is similar to that which is produced during an earthquake before the main shock wave is generated.

(a) What type of sounds are (i) X, (ii) Y, and (iii) Z?

(b) Name one device which can produce sound like X.

(c) Name one device in a science laboratory which can produce sound like Y.

(d) Name one device in our homes which can produce sound like Z.

(e) What is the frequency range of sounds like Z?

What is kidnapped, blindfolded and imprisoned in a big room. How could the man tell if he was in:

(a) a city (b) a village

(c) a bare room (d) a furnished room?