Dear students,

Find below some of the fill in the blanks questions  from the chapter sound. (Class 9 Science) Practisinf fill in the blanks typwe questions helps better comprehension and thorough reading of the text book. As a follow up you can try making more fill in the blanks type questions yourself from the textbook.

1. ______ is a form of energy which produces a sensation of hearing to our ears.
2. λ is a symbol of representing _____________.
3. __________ is the reciprocal of frequency.
4. Mechanical waves are of two types; _____________ and ______________.
5. Sound waves travel in the form of ____________ and __________________.
6. Transverse waves propagate in the form of _________ and _____________.
7. The maximum displacement of the wave from mean position is called ______________.
8. Number of vibrations completed in one second is called ________________.
9. The distance between two consecutive compressions or two consecutive rarefactions is called ______________.
10. Sound of frequency below 20 Hz is called _____________
11. velocity of sound = ___________ x wavelenth
12. Sound cannot travel in _____________
13. Sound of frequency greater than 20 kHz is called ___________
14. _______________ is used to check abnormalities of fetus.
15. SI unit of frequency is _________.
16. ____________ is a device used to measure the depth of sea.
17. SONAR’s full form is __________________________________
18. Sound travels fastest in ____ medium
19. Loudness of sound depend on _____ of vibration.
20. Audible range for human beings is from _ Hz to ___ Hz.
21. Bats detect their prey using ___________– waves.
22. Sound heard after reflection from an obstacle or boundary is called ________-.
23. The persistence of sound after the source has stopped vibrations is called ________.
24. ___________ is a device used by doctors and its working is based on multiple reflection of sound.
25. Loudness of sound is determined by the ___________ of vibrations.
26. Checking the functioning of heart with the help of ultrasound is called ________________
27. The outer ear is also called ________
28. Another function of human ear is to _____________ our body.
29. _______ of ear collects sound from the surroundings.
30. Ultrasound are produced by some animals like __________, _____________ and _____________.
31. Electrical signals from ear are send to the brain via _____________
32. The three bones of the ear which amplifies the vibrations are _______ , ______________ and ____________.
33. ______________ converts sound into electrical signals.
34. The smallest bone in ear is __________ which is also the smallest bone in human body.
35. ____________ are regions of higher density and pressure when sound propagates through a medium.