Maharashtra Board 9th Science MCQ on Topic 12. Study of Sound

) Echocardiography studies using ultrasound scans.

A ) Nerves

B ) Abdomen C ) Heartbeats D ) Brain

Ans C ) Heartbeats

) The time taken by a particle to complete one oscillation is called the of the wave.

A ) Amplitude

B ) Period

C ) Frequency

D ) Wavelength

Ans B ) Period

) Sonography method is and hence is increasingly used in medical practice for correct diagnosis.

A ) Painful

B ) Painless

C ) Challenging

D ) Costly

Ans B ) Painless

) The technique of Sonography makes use of a …………… and ……………

A ) Gel and probe

B ) Gel and camera

C ) Camera and sound

D ) None of these

Ans A ) Gel and probe

) Clothes, Papers, Curtains, etc. absorb sound instead of reflecting it.

A ) True

B ) False

Ans A ) True

) For a fix temperature, the velocity of sound does not depend on the ……………

A ) Molecular weight

B ) Density

C ) Temperature

D ) Pressure

Ans D ) Pressure

.

) The part of the ear that converts vibration coming from membrane into electrical signals.

A ) Outer ear B ) Cochlea C ) Eardrum

Ans B ) Cochlea

) If the frequency of radio waves is 530 MHz, then the wavelength of radio waves is (c = 3 x 108

m/s)

A ) 0.56 m B ) 5.6 m C ) 56.6 m D ) 0.75 m

Ans A ) 0.56 m

) A boat at anchor is rocked by waves whose crests are 100 feet. apart and whose velocity is 25 ft/sec. The time taken by each wave to reach the boat is …………………

A ) 4 s

B ) 0.25 s C ) 2500 s D ) 0.125 s

Ans A ) 4 s

) If the distance between two successive compressions in propagation of a longitudinal wave in a medium is

0.5 m & the frequency is 300 hz, the wave speed is ……………….

A ) 750 m/s B ) 300 m/s C ) 450 m/s D ) 150 m/s

Ans D ) 150 m/s

) The velocity of sound is to the square root of density of the medium.

A ) Directly proportional B ) Inversely proportional C ) Equal

D ) Almost equal

Ans B ) Inversely proportional

) To hear an echo, the total distance covered by sound from the point of generation to the reflecting surface and back should be atleast ………………

A ) 36 m B ) 17.2 m C ) 34.4 m D ) 19 m.

Ans C ) 34.4 m

) Milk is sterilized by killingThere was .afnorerarolor nstgarstihneglfthliefeapupsliincagtiuolntr.aPsleoausned.try

A ) Fungus B ) Bacteria C ) Virus

D ) None of these

Ans B ) Bacteria

..

) The velocity of sound is to the square root of the temperature of the medium.

A ) Directly proportional B ) Inversely proportional C ) Equal

D ) Almost equal

Ans A ) Directly proportional

) Sound produced by the pendulum is ……………

A ) Audible sound

B ) Infra sound

C ) Ultrasound

D ) None of these

Ans B ) Infra sound

) Velocity of sound is highest in ……………

A ) Solids B ) Liquids C ) Gases

Ans A ) Solids

) If the molecular weight of the gas is increased four times, then the velocity of the sound to half of

its value.

A ) Increases B ) Doubles C ) Reduces

D ) None of these

Ans C ) Reduces

) Sound is a form of ……………..

A ) Energy

B ) Reflection

C ) Vibration

D ) Reverberation

Ans A ) Energy

) Sound is a form of energy which creates the sensation of hearing in our ears.

A ) True

B ) False

.

Ans A ) True

..

) Sound waves with frequency greater than 20KHz are called ……………

A ) Audible sound

B ) Infra sound

C ) Ultrasound

D ) None of these

Ans C ) Ultrasound

) Find the odd one out

A ) Temperature

B ) Density

C ) Molecular weight

D ) Pressure

Ans D ) Pressure

) Find the odd one out.

A ) Bats B ) Rats C ) Cats

D ) Dolphins

Ans C ) Cats

) is a region where the particles of the medium are well separated from each other during the

propagation of longitudinal wave.

A ) Crests

B ) Compressions

C ) Trough

D ) Rarefaction

Ans D ) Rarefaction

) To locate the cracks and faults in metal blocks ultrasound is used.

A ) True

B ) False

Ans A ) True

) Which of the following is different from others?

A ) Wavelength

B ) Velocity

C ) Frequency

D ) Amplitude

Ans D ) Amplitude

) are used to establish ship to ship communication.

A ) Ultrasounds

.

B ) Sonicsounds

C ) Supersonic sounds

D ) Infrasounds

Ans A ) Ultrasounds

..

) The amplitude of sound determines its ……………

A ) Quality

B ) Pitch

C ) Loudness

D ) Wavelength

Ans C ) Loudness

) The nerve that connects inner ear to brain.

A ) Sensory nerve B ) Auditory nerve C ) Olfactory nerve

Ans B ) Auditory nerve

) If the time period of an oscillation is tripled, then the frequency becomes its original.

A ) 3 times

B ) 1 / 3

C ) 1 / 9

D ) 9 times

Ans B ) 1 / 3

) At rarefactions in medium, density as well as pressure is ………………

A ) High

B ) Low

C ) Infinite

D ) Zero

Ans B ) Low

) wave is a wave in which the particles of the medium vibrate in a direction parallel to the direction

of propagation of the wave.

A ) Electromagnetic

B ) Transverse

C ) Polarised

D ) Longitudinal

Ans D ) Longitudinal

) sound has frequency below 20 hz and is not audible to human beings.

A ) Ultrasonic

B ) Sonic

C ) Infrasonic

.

D ) Supersonic

Ans C ) Infrasonic

..

) The maximum displacement of a particle from its mean position is called its …………………

A ) Amplitude

B ) Period

C ) Frequency

D ) Wavelength

Ans A ) Amplitude

) To discover a sunken ship or objects deep inside the sea, technology is used.

A ) Refraction

B ) Reverberation

C ) SONAR

D ) Wave

Ans C ) SONAR

) Images of the internal organs in a human body can be obtained using ……………

A ) Ultrasound

B ) Infrasound

C ) Audible sound

D ) NMR

Ans A ) Ultrasound

) SONAR has a …………… and , which are fitted on ships or boats.

A ) Absorber, reflector

B ) Absorber, transmitter C ) Transmitter, receiver D ) Reflector, receiver

Ans C ) Transmitter, receiver

) The velocity of sound is inversely proportional to the ……………

A ) Pressure

B ) Square root of density

C ) Square root of temperature

D ) Humidity

Ans B ) Square root of density

) sound has frequency between 20 hz – 20000 hz and is audible to human beings.

A ) Ultrasonic

B ) Sonic

C ) Infrasonic

D ) Supersonic

.

Ans B ) Sonic

..

) The velocity of sound in air at 22°C is …………………….

A ) 384 m/s B ) 244 m/s C ) 344 m/s D ) 284 m/s

Ans C ) 344 m/s

) A person observes a smoke from the cannon. After 1.5 seconds, he hears the bang. If the cannon is 510 m away from the observer, the velocity of sound in air is .……………

A ) 240 m B ) 340 m C ) 140 m D ) 340 m

Ans B ) 340 m

) Bats can produce sounds.

A ) Infrasonic

B ) Loud

C ) Ultrasonic

D ) Low quality

Ans C ) Ultrasonic

) In some auditoriums, due to inferior sound reception we hear ……………

A ) Echo

B ) Reverberation

C ) Noise

D ) None of these

Ans B ) Reverberation

) The time taken for one oscillation is called the Time period.

A ) False

B ) True

Ans B ) True

) Speed of sound increases with an increase in ……………

A ) Molecular weight

B ) Density

C ) Temperature

D ) Pressure

Ans C ) Temperature

) In a single sound can be heard continuously.

A ) Echo

.

B ) Reverberation

C ) Medium

D ) None of these

Ans B ) Reverberation

..

) Velocity of sound depends on temperature of air

A ) False

B ) True

Ans B ) True

) Under similar conditions of temperature and pressure in which of the following gases will the velocity of sound be least?

A ) O2

B ) H2 C ) CO2 D ) N2

Ans C ) CO2

) The velocity of sound increases as the temperature is increased. This increase is:

A ) 0.61 ms-1/°C B ) 61 ms-1/°C C ) 30.5 ms-1/°C

D ) 0.305 ms-1/°C

Ans A ) 0.61 ms-1/°C

) Communication between ships at sea is carried out using ……………

A ) Radar

B ) Ultrasound

C ) Infrasound

D ) Nautical miles

Ans C ) Infrasound

) The incident sound waves and the reflected sound waves are on the of the normal.

A ) Same side

B ) Opposite sides C ) Left hand side D ) Right hand side

Ans B ) Opposite sides

) Repetition of the original sound because of reflection of sound is called ………………..

A ) Reflection B ) Refraction C ) Echo

D ) Reverberation

.

Ans C ) Echo

..

) Children under the age of can hear upto 25000 Hz.

A ) 12

B ) 15

C ) 7

D ) 5

Ans D ) 5

) The technique was first developed during world war I to detect enemy submarines.

A ) Refraction

B ) Reverberation

C ) Wave

D ) SONAR

Ans D ) SONAR

) Intricate parts of the machines are cleaned using infrasound.

A ) True

B ) False

Ans B ) False

) The velocity of sound is maximum in ……………

A ) Solids B ) Liquids C ) Gases D ) Vacuum

Ans A ) Solids

) SONAR is used for ……………

A ) Searching icebergs

B ) Distance and speed of underwater object

C ) Depth of sea

D ) All of these

Ans D ) All of these

) in the objects are responsible for producing sound.

A ) Reflections

B ) Waves

C ) Reverberations

D ) Vibrations

Ans D ) Vibrations

) Sonography is useful in finding out ……………

A ) Condition of the heart

.

B ) State of the heart after a heart attack

C ) Growth of the fetus

D ) All of these

Ans D ) All of these

..

) The golghumat in Karnataka is perfect example for multiple reflection of sound.

A ) True

B ) False

Ans A ) True

) There should be materials to reduce reverberation in a room.

A ) Sound absorbing

B ) Precious C ) Reflecting D ) Glass

Ans A ) Sound absorbing

) The of the sound waves is indicated by the Greek letter lamba (λ).

A ) Frequency B ) Wavelength C ) Velocity

D ) Time period

Ans B ) Wavelength

) Sound waves get from a solid or a liquid surface.

A ) Absorbed B ) Refracted C ) Reflected D ) All of these

Ans C ) Reflected

) If the wavelength is 0.5 m & wave speed of the wave is 50 m/s, then the time period is …………………….

A ) 1 s

B ) 0.05 s C ) 0.01 s D ) 0.1 s

Ans C ) 0.01 s

) The incident sound and reflected sound wave make equal angles with the normal.

A ) True

B ) False

Ans A ) True

) The periodic time is second if the frequency of the wave is 100 Hz and the wavelength is 0.2 m.

A ) 20 s

.

B ) 2 s

C ) 1 s

D ) 0.01 s

Ans D ) 0.01 s

..

) Children under the age of 5 years can hear waves with frequency up to ……………

A ) 20Hz

B ) 25KHz

C ) Above 25kHz

D ) None of these

Ans B ) 25KHz

) is a region where the particles of the medium are crowded together during the propagation of

longitudinal wave.

A ) Crests

B ) Rarefaction

C ) Compressions

D ) Trough

Ans C ) Compressions

) Sonography technique can be used for sex determination during pregnancy.

A ) False

B ) True

Ans B ) True

) Longitudinal waves are created by dropping a stone in still water.

A ) False

B ) True

Ans A ) False

) A hard and flat surface is a good ……………

A ) Absorber B ) Reflector C ) Refractor

D ) None of these

Ans B ) Reflector

) The propagation of a sound wave is in form of alternate bands of compression and rarefaction.

A ) False

B ) True

Ans B ) True

) The sensation of sound persists in our brain for about …………………

A ) 1 second

B ) 10 second

.

C ) 0.01 second

D ) 0.1 second

Ans D ) 0.1 second

..

) is the phenomenon in which sound waves are reflected multiple times causing a single sound to

be heard more than once.

A ) Reflection

B ) Refraction

C ) Reverberation

D ) Persistence of sound.

Ans C ) Reverberation

) The normal hearing range for humans is ……………

A ) 20 to 20,000 Hz

B ) Greater than 20,000Hz

C ) 0 to 20Hz

D ) None of these

Ans A ) 20 to 20,000 Hz

) When a reaches the ear drum, the pressure outside the membrane increases and forces the

ear drum inwards.

A ) Rarefaction

B ) Crests

C ) Trough

D ) Compression

Ans D ) Compression

) A longitudinal wave is produced in a slinky toy. The wave travels at a speed of 40 cm/s and the frequency of the wave is 25 Hz. The minimum separation between the consecutive compressions of the slinky is

…………………

A ) 2

B ) 0.625 cm

C ) 1.6 cm

D ) 1.2 cm

Ans C ) 1.6 cm

) technology uses ultrasound waves to generate images of internal organs of the human body.

A ) X rays

B ) Cardiograph C ) Sonography D ) All of these

Ans C ) Sonography

) During the propagation of the wave through a medium, the do not change their positions.

A ) Properties

.

B ) Particles

C ) Waves

D ) Vibrations

Ans B ) Particles

..

) SONAR consists of a and a detector.

A ) Transmitter

B ) Reflector C ) Refractor D ) Deflector

Ans A ) Transmitter

) Pitch of sound depends upon of the wave.

A ) Quality

B ) Frequency C ) Loudness D ) Wavelength

Ans B ) Frequency

) In SONAR, R stands for …………….

A ) Radar

B ) Reflected C ) Ranging D ) Receiving

Ans C ) Ranging

) During the propagation of sound wave through a medium, there is a change in density and of

the medium.

A ) Pressure B ) Texture C ) State

D ) Pitch

Ans A ) Pressure

) The incident sound wave, reflected sound wave and the normal lie in different planes.

A ) True

B ) False

Ans B ) False

) Longitudinal waves consist of alternate …………… and ……………

A ) Crests & troughs

B ) Waxing and waning

C ) Compressions & rarefactions Electric and magnetic field vectors

D )

.

Ans Compressions & rarefactions ..

C )

) The value of amplitude determines the loudness of the sound.

A ) False

B ) True

Ans B ) True

) Thin membrane in the cavity of the middle ear.

A ) Stapes

B ) Eardrum

C ) Eustachian tube

Ans B ) Eardrum

) Ultrasonic sounds have frequency ……………

A ) Less than 20 hz B ) Above 10000 hz C ) Above 20000 hz D ) Below 20000 hz

Ans C ) Above 20000 hz

) Our brain retains sound for 0.1second.

A ) True

B ) False

Ans A ) True

) If the temperature of the medium is increased four times, then the velocity of the sound ……………

A ) Remains the same

B ) Doubles

C ) Reduces

D ) Increases four times

Ans B ) Doubles

) In Sonography, the sound reflected from the internal organs is fed into computer to get the images.

A ) True

B ) False

Ans A ) True

91 )

Column

– A

Column

– B

i. Outer ear a. Eardrum
ii. Middle ear
b. Pinna
c. Cochlea

.

in.

Column

– A

Columnaga

– B

i. Outer ear a. Cochlea
ii. Middle ear
b. Pinna
Column

– A

Column

– B

i. Outer ear
a. Pinna
ii. Middle ear b. Eardrum

A )

B )

C )

Ans

Column

– A

Column

– B

i. Outer ear
a. Pinna
ii. Middle ear b. Eardrum

B )

) Bats, mice , dolphins can produce ……………

A ) Audible sound

B ) Infra sound

C ) Ultrasound

D ) None of these

Ans C ) Ultrasound

) Which of the statements is not true for the sound waves?

A ) Sound travels faster in water than in air.

B ) Sound travels as a longitudinal wave in a gas.

Due to the propagation of sound, compressions and rarefactions are set up in gaseous

C ) medium.

D ) Presence of moisture in atmosphere does not affect the speed of sound. Ans D ) Presence of moisture in atmosphere does not affect the speed of sound. 94 ) Sound does not travel through ……………

A ) Glass

B ) Vacuum

C ) Pure water

Ans B ) Vacuum

) For sound waves, the angle of incidence is the angle of reflection.

A ) Greater than

B ) Less than

C ) Equal to

D ) Parallel to

.

Ans C ) Equal to

..

) Female foeticide is now a cognizable offence in India.

A ) True

B ) False

Ans A ) True

) is the relation between the frequency (υ) & time period (T) of a sound wave.

A ) υ = T

B ) υ = λT

C ) υ = 1 / T

D ) λυ = T

Ans C ) υ = 1 / T

) is the maximum value of pressure or density indicated by A.

A ) Frequency

B ) Velocity

C ) Amplitude

D ) Wavelength

Ans C ) Amplitude

) If the frequency of the wave is 100 Hz and its wavelength is 0.2 m, then its wave speed is ……………….

A ) 20 m/s B ) 75 m/s C ) 300 m/s D ) 600 m/s

Ans A ) 20 m/s

) waves gives rise to a chain of compression and rarefaction.

A ) Light

B ) Medium C ) Sound D ) Large

Ans C ) Sound

) The value of frequency determines the of the sound.

A ) Noise B ) Music C ) Pitch

D ) All of these

Ans C ) Pitch

) The velocity of sound in air is at 0°C as compared to room temperature.

A ) More

.

B ) Less C ) Infinite D ) Zero

Ans B ) Less

..

) The speed of sound in air at 0°C is 332 m/s. The velocity of sound in air at 20°C is ……………………

A ) 344 m/s B ) 364 m/s C ) 384 m/s D ) 324 m/s

Ans A ) 344 m/s

) In waves, particles oscillate up and down about their mean positions.

A ) Electromagnetic

B ) Transverse

C ) Polarised

D ) Longitudinal

Ans B ) Transverse

) A person standing before a cliff shouts & hears the echo after 1.6 seconds. If the speed of sound in air is 340 m/s, the distance between the person and cliff is ………………..

A ) 544 m B ) 272 m C ) 292 m D ) 212.5 m

Ans B ) 272 m

) A smooth surface is required for the reflection of sound.

A ) True

B ) False

Ans A ) True

) Mirror is a good absorber of sound.

A ) False

B ) True

Ans A ) False

) The distance between two consecutive crests in a wave produced in string is 5 cm. If two complete waves pass through any point per second, then the velocity of the wave is ……….………

A ) 2.5 m/s B ) 10 m/s C ) 5 m/s D ) 20 m/s

Ans B ) 10 m/s

.

) For an echo to be heard distinctly, the minimum distance from the source is 34.4 m

..

A ) True

B ) False

Ans B ) False

) Borelli and Viviani were the first to calculate the of sound.

A ) Wavelength

B ) Density C ) Pressure D ) Speed

Ans D ) Speed

) The speed of sound in air

A ) 340m/s2 B ) 330m/s C ) 340m/s

Ans C ) 340m/s

) If the density of oxygen is 16 times to that of hydrogen, the corresponding ratio of velocity of sound is

………………

A ) 1 : 4

B ) 4 : 1

C ) 2 : 1

D ) 1 : 16

Ans A ) 1 : 4

) If the time period of oscillation is 0.05s, the frequency of sound wave is ………………..

A ) 10 Hz B ) 20 Hz C ) 30 Hz D ) 40 Hz

Ans B ) 20 Hz

) SONAR is based on technology.

A ) Infrasound B ) Ultrasound C ) Radar

D ) None of these

Ans B ) Ultrasound

) SONAR stands for ……………

A ) Sound Naval & Regional system

B ) Sound Newsletter & Ringing system

C ) Sound Nomination & RTohaemreinwgas asnteemrror starting the application. Please try

D ) Sound Navigation & Ranging system.

..

Ans D ) Sound Navigation & Ranging system.

) Peculiar funnel like shape that collects and passes sounds into the middle ear.

A ) Middle ear B ) Outer ear C ) Inner ear

Ans B ) Outer ear

) Echo can be heard multiple times due to continuous reflections.

A ) True

B ) False

Ans A ) True

) A is necessary for the propagation of sound waves.

A ) Light

B ) Sound

C ) Medium

D ) Pressure

Ans C ) Medium

) An echo is the repetition of the original sound.

A ) True

B ) False

Ans A ) True

) Velocity of sound is lowest in ………….. .

A ) Solids B ) Liquids C ) Gases

Ans C ) Gases

) The structure resembling the shell of a snail.

A ) Tympanic cavity

B ) Pinna

C ) Cochlea

Ans C ) Cochlea

) Sound waves are waves.

A ) Electromagnetic

B ) Transverse

C ) Polarised

D ) Longitudinal

Ans D ) Longitudinal

.

) Velocity of the sound wave is given by the formula.

..

A ) Velocity=Time/ Distance

B ) Velocity = Wavelength x Frequency

C ) Velocity = Time period/ Wavelength

Ans B ) Velocity = Wavelength x Frequency

.

 

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