SOUND FILL IN THE BLANKS and NOTES ICSE CLASS 8

SOUND MCQ

SOUND TRUE AND FALSE

Fill in The Blanks

1. Unit of loudness is ........................

2. Any sound above 8S dB can cause ........................

3. Sound is a form of..................... which excites in our ears the ..................... of hearing.

4. Pitch is a sensation which determines ..................... of sound.

5. ........................ is a continuous sound especially of someone speaking, that doesn’t change in pitch.

Answers

Fill in The Blanks

1. decibel

2. damage to our ears

3. energy, sensation

4. shrillness

5. monotone

WORKSHEET

1. Fill in the blanks

(a) The time period of a wave is 2 s. Its frequency is 0.5 S-1.

(b) The pitch of a stringed instrument is increased by increasing tension in string.

(c) The pitch of a flute is decreased by increasing length of air column.(d) Smaller the membrane, higher is the pitch.

(e) If a drum is beaten hard, its loudness increases.

(f) A tuning fork produces sound of single frequency.

WORKSHEET

2.  Fill in the blanks

1. Loudness of a sound ………… with increase in the distance between the listener and the source.

2. The characteristic of a sound which distinguishes a shrill sound from a hoarse one is called ………….

3. A longer string will produce a sound of a …………. pitch.

4. Drum produces sound due to vibration of its …………

5. Unpleasant sound that is very loud is called …………

6. Humans can pick up sounds in the range of to ………….

7. Sound of about …………. decibels or more causes many health hazards.

8. Constant exposure to sounds above 80 dB can cause ………….

Answer:

1. Loudness of a sound decreases with increase in the distance between the listener and the source.

2. The characteristic of a sound which distinguishes a shrill sound from a hoarse one is called pitch.

3. A longer string will produce a sound of a lower pitch.

4. Drum produces sound due to vibration of its stretched membrane.

5. Unpleasant sound that is very loud is called noise.

6. Humans can pick up sounds in the range of to 10 dB to 180 dB.

7. Sound of about 80 dB decibels or more causes many health hazards.

8. Constant exposure to sounds above 80 dB can cause health problems.

Define the following

Amplitude

The maximum displacement of a wave on either side of its mean position is known as its amplitude.

Frequency

Frequency of a wave is the number of oscillations completed by it in one second.

Time period

Time period of a wave is the time taken by it to complete one oscillation.

Loudness Loudness is a characteristic of sound which distinguishes a feeble sound from a loud one of the same frequency.

Pitch

The characteristic of sound that differentiates a shrill sound from a hoarse sound is called pitch.

Timbre

Timbre distinguishes two notes of the same pitch (or frequency) and loudness (or amplitude) produced by different bodies.

Monotone

A sound which never changes or goes up or down is called a monotone. A monotone sound never changes in pitch, loudness, timbre or in speed.

Music A sound that has a pleasing sensation on our ears and is produced due to regular vibrations is called music.

 Noise A sound unpleasant to our ears and is produced by irregular vibrations is called noise.

Select the Odd and Out Giving reason

1. Veena, trumpet, tanpura, guitar.

2. Tabla, drum, flute, dhol.

3. Guitar string, human vocal cords, diaphragm of a loudspeaker, whistle, frequency.

Answers

Select the Odd and Out Giving reason

1. Trumpet : It is a wind instrument others are string instruments.

2. Flute : others are percussion instruments

3. Frequency : it is physical quantity others are instruments

•  CHARACTERISTICS OF SOUND : (i) Loudness. (ii) Pitch (or shrillness). (iii) Quality (or timbre or wave form). LOUDNESS : is the characteristic of sound by virtue of which a loud sound can be distinguished from a faint sound, both having same frequency and same wave form.

Give one Word for The Followings

1. Form of energy that produces a sense of hearing.

2. The sensation which determines the shrillness of sound.

3. Unit used to measure the loudness of sound.

4. High-pitched sounds are known as.

5. Unit of frequency.

Answers

Give one Word for The Followings

1. Sound

2. Pitch

3. Decibel

4. Treble

5. Hertz

• SOUND: “Is energy which produces in us the sensation of hearing.” It is produced by vibration of body.

• Sound needs a medium for its propagation. Sound cannot travel in vacuum.

• Speed of sound is maximum in solids. 5000 ms-1 in steel, in water 1500 ms-1 and in air it is least 330 ms-1 nearly.

• When a body vibrates, the particles of medium also start vibrating and K.E. of particles changes into potential energy and P.E. into K.E. This is why sound in energy.

•  Sound travels in a medium in the form of wave.
  

• Longitudinal wave : When the particles of medium move in the direction of motion of wave by forming compression and rarefaction.
  

• AMPLITUDE : “The maximum displacement of the particle of medium on either side of mean position.”
  

• TIME PERIOD: “The time taken by a particle of medium to complete its one vibration” “t”

•  FREQUENCY: “The number of vibrations made by a particle of the medium in one second. ƒ measured in Hertz (Hz)

•  FREQUENCY  ƒ = 1/ t or t = 1 / ƒ

•  WAVE LENGTH: “The distance travelled by the wave in one one time period of vibration of particle of medium.” Or “The distance between two consecutive compressions or between two consecutive rarefactions.” It is denoted by ‘ λ ’ and S.I. unit of wave length is metre (m).

• It depend on: (i) Amplitude of wave (ii) Surface area of vibrating body (ii) Distance from the source of sound (iv) Sensitivity of listener: Unit of loudness is (dB) decibel.

•  PITCH: It depends on number of vibrations per second or frequency : more frequency is high pitch shrilled sound and low frequency is flat sound.

•  QUALITY: is the characteristic which distinguishes two sounds’of the same pitch and same loudness. It depends on wave form.

1. The time taken by a wave to complete one oscillation is called its ……….

2. Loudness of a sound decreases with …………. in its amplitude.

3. A shrill voice has …………… frequency.

4. The ………….. distinguishes the sounds of a guitar and a bongo with the same pitch and loudness.

Answer:

1. The time taken by a wave to complete one oscillation is called its time period

2. Loudness of a sound decreases with decrease in its amplitude.

3. A shrill voice has larger frequency.

4. The timbre distinguishes the sounds of a guitar and a bongo with the same pitch and loudness.

SOUND T & F ICSE CLASS 8

SOUND FILL IN THE BLANKS AND NOTES

SOUND MCQ

Write True Or False

1. Sound waves travel faster in air than in water.

2. Sound waves do propagate in vacuum.

3. The unpleasant sounds are called noises.

4. The amplitude of a sound depends upon the force applied in vibrating the sound producing object.

5. Women have loud voice in comparison to men.

Answers

Write True Or False

1. False

2. False

3. True

4. False

5. False

WORKSHEET

1. Write true or false for each statement

(a) When sound propagates in air, it does not carry energy with it.

Answer. False.

(b) In a longitudinal wave, compression and rarefaction are formed.

Answer. True.

(c) The distance from one compression to nearest rarefaction is called wavelength.

Answer. False.

(d) The frequency is measured in second.

Answer. False.

(e) The quality of a sound depends on the amplitude of wave.

Answer. False.

(f) The pitch of sound depends on frequency.

Answer. True.

(g) Decibel is the unit of pitch of a sound.

Answer. False.

Question 1.

A sound with higher amplitude is a soft sound whereas a sound with lower amplitude is loud.

Answer:

False.

Correct : A sound with higher amplitude is a loud sound whereas a sound with lower amplitude is a soft sound.

Question 2.

The pitch of a sound of string instruments decreases with the decrease in the thickness of the vibrating string.

Answer:

False.

Correct : The pitch of a sound of string instruments decreases with increase in the thickness of the vibrating string.

Question 3.

Pitch of a sound depends on its frequency.

Answer:

True.

Question 4.

The pitch of a stringed instrument depends on the tension in the string.

Answer:

True.

Question 5.

A flute produces sound due to vibration of air column inside it.

Answer:

True.

Question 6.

Music has a disturbing effect on health and behaviour of a person.

Answer:

False.

Correct : Noise has a disturbing effect on health and behaviour of a person.

Question 7.

Sounds below 50 dB cause noise pollution arid are harmful.

Answer:

False.

Correct : Sounds above 80 dB can cause noise pollution and are harmful.

Question 8.

Percussion instruments produce sound due to the vibration of thin metal strips.

Answer:

False.

Correct : Percussion instruments produce sound by a vibrating stretched membrane or by vibration of their whole bodies.

SOUND MCQ ICSE CLASS 8

SOUND FILL IN THE BLANKS AND NOTES

SOUND TRUE AND FALSE

Tick (✔) The correct choice amongest the following

1. Sound is a form of : (a) energy(b) wave(c) disturbance(d) all of these

2. Sound travels fastest in : (a) solids(b) liquids(c) gases(d) vacuum

3. The loudness of a sound (a) amplitude(b) pitch(c) velocity(d) wavelength

4. Loudness is a sensation depending upon : (a) time period(b) phase(c) frequency(d) intensity

5. Hertz is a unit of : (a) time period(b) wavelength(c) frequency(d) wave speed

Answers

Tick (✔) The correct choice amongest the following

1. (a) energy

2. (a) solids

3. (a) amplitude

4. (a) time period

5. (c) frequency

WORKSHEET

Select the correct alternative

(a) Sound can not travel in

1.  solid

2.  liquid

3.  gas

4.  vacuum

(b) When sound travels in form of a wave

1. the particles of medium move from the source to the listener

2.  the particles of medium remains stationary

3.  the particles of medium start vibrating up and down

4.  the particles of medium transfer energy without leaving their mean positions.

(c) The safe limit of loudness of audible sound is

1.  0 to 80 dB

2.  above 80 dB

3.  120 dB

4.  above 120 dB

(d) The unit of loudness is

1.  cm

2.  second

3.  hertz

4.  decibel

(e) In a piano, pitch is decreased by

1.  using thicker string

2.  increasing tension

3.  reducing length of string

4.  striking it hard
   

1. Loudness of a sound depends on the a. the wavelength of sound. b. volume of air around the vibrating body. c. time. d. none of these Answer:d. none of these

2.The pitch of a sound increases with increase in its a. frequency. b. loudness. c. amplitude. d. time period. Answer:a. frequency.

3.The pitch of a flute can be increased by

a. increasing the length of its vibrating air column.

b. decreasing the length of its vibrating air column.

c. increasing the length of its vibrating string.

d. decreasing the length of its vibrating string.

Answer:

b. decreasing the length of its vibrating air column.

4.A sound produced by guitar and violin with the same pitch and loudness is distinguished by its

a. frequency.

b. amplitude.

c. timbre.

d. time period.

answer:

c. timbre.

5.Which of the following properties of sound is responsible for its loudness?

a. frequency

b. pitch

c. amplitude

d. quality

Answer:

c. amplitude

6.Musical sounds are caused due to –

a. regular vibrations.

b. irregular vibrations.

c. damped vibrations.

d. none of these

Answer:

a. regular vibrations.

7.The sound that never changes in pitch, volume, speed or timbre is known as –

a. monologue.

b. monolingual.

c. monophony.

d. monotone.

Answer:

d. monotone.

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