please give some numericals from sound with solutions

hi, 

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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 _____________

1. velocity of sound = ___________ x wavelenth
2. Sound cannot travel in _____________
3. Sound of frequency greater than 20 kHz is called ___________
4. _______________ is used to check abnormalities of fetus.
5. SI unit of frequency is ________

Q1) there is an electric motor of 5kwt. If its height is 20m then how many water it will release in one minute(take g= 10m/s²)

Q2) There is a man standing on top floor of his house. He was wearing helmet . His helmet slip down from his head at the height of 78.4m. After 4.23 sec. he hear the sound. Find the speed of helmet and speed of sound in air?