Q1. Fill in the blanks.
Time taken by an object to complete one
oscillation is called time period.
Loudness is determined by the amplitude
The unit of frequency is hertz (Hz).
Unwanted sound is called noise.
Shrillness of a sound is determined by the frequency
Higher the frequency of vibration,
the higher is the pitch, and shriller is the sound.
Sound which is pleasing to the ear is
called musical sound.
Q2. State True (T) or False (F).
Sound cannot travel in vacuum. T
The number of oscillations per second of a
vibrating object is called its time period. F
If the amplitude of vibration is large,
sound is feeble. F
For human ears, the audible range is 20 Hz
to 20,000 Hz. T
The lower the frequency of vibration, the
higher is the pitch. F
Unwanted or unpleasant sound is termed as
Noise pollution may cause partial hearing
Q3. Name one animal which can hear ultrasonic sounds.
Q4. How is sound produced?
Ans. Sound is produced by vibrating objects.
Q5. How does an object produce sound?
Ans. Sound is produced when an objects vibrates.
Q6. Name the sound producing organ in humans.
Ans. Voice box (larynx)
Q7. Name the organs of hearing in our body.
Ans. Our ears are the organs of hearing in our body.
Q8. Name that part of ear which vibrates when outside sound
falls on it.
Ans. Eardrum vibrates when outside sound falls on it.
Q9. Name the unit used to measure the loudness of sound.
Ans. The loudness is expressed in a unit called
Q10. Name the quantity whose unit is 'hertz'.
Ans. The unit of frequency is called “hertz”.
Q11. Does any part of the body vibrate when we speak? Name the
Ans. Yes, vocal chords vibrate when we speak.
Q12. On what factor does the pitch of a sound depend?
Ans. The frequency determines the shrillness or pitch
of a sound.
Q13. What is the name of passage in outer ear which carries
sound waves to the eardrum?
Ans. The sound is carried through the Ear canal.
Q14. Choose the correct answer: Sound can travel through
(a) gases only (b)
(c) liquids only (d)
solids, liquids and gases.
(d) solids, liquids and gases.
Q15. Which of the following voices is likely to have minimum
(a) Baby girl (b)
(c) A man (d) A
(c) A man
Q16. What is frequency of
Ans. The number of oscillations per second is called
the frequency of oscillation.
Q17. What is the audible range of frequencies for human ears?
Ans. For human ear, the range of audible frequencies
is roughly from 20 to 20,000 Hz.
Q18. What is vibration?
The to and fro or back and forth motion of an object is termed as vibration.
Q19. How does a sound producing object differ from silent?
Ans. A sound producing object vibrates while a silent
does not. We can feel the vibrations by touching them.
Q20. What brings the sound of a ringing telephone bell to our
Ans. The sound of a ringing telephone bell travel to
our ears through the air in the room.