SOUND

SOUND
HOTS

1.   Do all bodies produce sound?

2.   Touch the bell when it stops producing sound. Can you feel the vibration? What do you understand by this?

3.   Name the sound producing organ.

4.   Can sound travel through vacuum?

5.   What is oscillatory motion?

6.   Why the sound of the baby is feeble?

7.   What is ektara? Identify its vibration part.

8.   Explain that sound travels in liquids as well.

9.   Name some musical parts and their vibrating parts

10.   How does shrillness or pitch is affected by frequency?

1.  Eardrum is a part of

      a.  Sound producing organ

      b.  Skeletal system

      c.  Hearing organ

      d.  Reproductive organ

2.   The hearing range of human ear is

      a.  20 Hz to 20,000 Hz

      b.  Less than20 Hz

      c.  More than 20,000 Hz

      d.  20 Hz to 25,000 Hz

3.   The voice box is called:

      a.  Stomach

      b.  Heart

      c.  Larynx

      d.  Mouth

4.   Large amplitude of sound vibrations will produce:

      a.  Loud sound

      b.  Meak sound

      c.  Slow sound

      d.  Shreak

5.   The pitch of sound depends on

      a.  frequency

      b.  amplitude

      c.  both of these

      d.  none of these

6.   Sound is kind of

      a.  Work

      b.  Energy

      c.  Force

      d.  None

7.   To an fro motion of an object is called

      a.  Waves

      b.  Amplitude

      c.  Vibration

      d.  All of the above

8.   Voice box or larynx of human process

      a.  Sound

      b.  Wind

      c.  Loudness

      d.  None

9.   Sound propagates maximum in

      a.  Gas

      b.  Liquid

      c.  Solid

      d.  All

10.   Noise pollution is harmful for

      a.  Human

      b.  Cat

      c.  Bird

      d.  All

ANSWERS

1.    C

2.    A

3.    C

4.    A

5.    A

6.    B

7.    C

8.    A

9.    c

10. D

1.   What do you meant by vibrations?

2.   What is the other name for larynx?

3.   Do all animals produce sound by vocal chords?

4.   Write the unit of frequency.

5.   What do you mean by noise pollution?

6.   What is the loudness of a normal conversation?

7.   Explain importance of sound in our daily life.

8.   Name the organ in human that produces sound. How does it work?

9.   Prove that sound travels in solids too.

10.   How does loudness of sound is affected by amplitude?

QUESTIONS FROM TEXTBOOK

Q.1.   Choose t.e correct answer. Sound can travel through:

           (a) gases only

(b) solids only

           (c) liquids only

(d) solids, liquids and gases.

Ans. (d) solids, liquids and gases.

Q.2.   Voice of which of following is likely to have minimum frequency?

           (a) Baby girl

(b) By boy

           (c) A man

(d) A woman..

Ans. (a) Baby girl.

Q.3.   In the following statements, tick 'T� again t hose which arse tare, ara ‘F’ against the which are false:

           (a) Sound cannot trarl in vacuum.

           (b) The number of oscillations per second of a vibrating objet is called its time period.

           (c) If the amplitude of vibration is large, sound is feeble.

           (d) For human ears, the audible range is 20 Hz to 20,000 .

           (e) The lower the frequency of vibration, the higher is the pitch.

           (f) Unwanted or unpleasant sound termed as music.

           (g) Noise pollution may cause partial hearing impairrraent.

Ans. (a) True (b) False (c) False

           (e) False (f) False (g) True.

Q.4.   Fill in the blanks ith suitable words:

           (a) Time taken by an object to a complete one oscillation is called__________.

           (b) Loudness as determined the ___________of uibration.

           (c) unit of fqueracy is __________.

           (d) Unwanted sound is called __________.

           (e) Shrillness of a sound is determined by the __________ of vibration.

Ans. (a) time period (b) amplitude (c) hertz (d) noise

           (e) frequency

Q.5.   A pendulum oscillates 40 times is 4 seconds. Find its time period and frequency.

Ans. Number of oscillations = 40

           Total time = 4 seconds

           

Q.6.   The sound from a mosquito i produced when it vibrates its wings at an average rate of 500 vibrations per seconds, what is the time period of the vibrations?

Ans. Total vibrations = 500

           Time taken = 1 second

           

           So time period = 0.002 seconds.

Q.7.   Identify the part which vibrates to produce sound in following instruments.

           (a) Dholak

(b) Sitar

(c) Flute.

Ans. (a) Stretched membrane

(b) Strings

(c) Air column.

Q.8.   What is the difference between noise and music? Can music become noise sometimes?

Ans. The sound which is unpleasant for our ears is called noise while music is the sound which is pleasant for our ears. Music becomes noise sometimes when it crosses the bearable range of sound for our ears.

Q.9.   List sources of noise pollution in your surroundings.

Ans. Sources of noise pollution: Honking of horns, loud speakers, loud sounds of machines in factories, loud sounds of T.V., radio, domestic appliances etc.

Q.10.   Explain in what way noise pollution is harmful to humans?

Ans. Harmful effects of noise pollution:

           (i) It causes deafness.

           (ii) It causes mental illness.

           (iii) It causes headache and high blood pressure.

Q.11.   Your parents are going to buy a house. They awe been offered one on the road side and another three ides away from the road side. Which house would you suggest your parents to buy? Explain your answer.

Ans. I would suggest my parents to buy house three lanes away from the roadside. This house would safeguard our health and peace of mind.

Q.12.   Sketch larynx and explain its function in your own words.

Ans. Larynx is also known as voice box. It has vocal cords which have air column vibrating in them, which cause sound in humans

Q.13.   Lightening an thunder take place in the sky at the same time and at the same distance from us. Lightning is seen earlier and thunder is heard later. Can you explain?

Ans. The speed of light is more than that of sound. Due to more speed the light reaches us before the sound does. So lightening is seen earlier and thunder is heard later.

SAMPLE PAPER QUESTIONS

1.   What do you meant by vibrations?

2.   What is the other name for larynx?

3.   Do all animals produce sound by vocal chords?

4.   Write the unit of frequency.

5.   What do you mean by noise pollution?

6.   What is the loudness of a normal conversation?

7.   Explain importance of sound in our daily life.

8.   Name the organ in human that produces sound. How does it work?

9.   Prove that sound travels in solids too.

10.   How does loudness of sound is affected by amplitude?

TEST

Maximum time: 35 minutes

Maximum marks: 20 marks

1.   What are the causes of noise pollution? (1)

2.   Define musical sound? (1)

3.   Which part of ear vibrates to produce sound? (1)

4.   Define ultra and infrasonic sounds. (2)

5.   What is the relation between loudness and amplitude of sound? (2)

6.   Write some applications of ultrasound in daily life. (4)

7.   How is the sound propagated? (2)

8.   Write any four sources of noise (4)

9.   What is the outer part of ear called? (1)

10.   Explain with the help of activity that vibrating bodies produce sound. (2)