CBSE Class 9 Physics Sound
- Can blackbox pings signal travel 3000kms? Can it be reflected on metal surface?
- Sound creates vibrations in our ear. We listen sound and understand it. But after this in which form of energy does it gets converted into?
- Why do animals like dogs etc get uneasy before earthquakes?
- How does a hearing aid work?
- How is ultrasound used in various industries?
- Which part of the ear contains the actual hearing organ?
- What causes temporary deafness in high altitude flying aircrafts?
- Draw labelled diagram of auditory parts of human ear and explain how the human ear works.
- (a) What are ultrasounds? Explain the use of ultrasounds in detecting defects in a metal block. (b) Explain how bats use ultrasounds to catch a prey? (c) Explain how moths of certain families are able to escape capture from a bat?
- (a) What does SONAR stand for? Explain its working stating one practical application. (b) A ship sends out ultrasound that returns from the seabed and is detected after 4s. If the speed of ultrasound through sea water is 1550 m/s, find the distance of the seabed from the ship.
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