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What sound is produced by earthquakes before the main shock waves?
- ultrasound
- infrasound
- audible sound
- None of the above
Answer
b. infrasound
Earthquakes produce infrasound waves before the main shock waves.
In compression and rarefaction, pressure density is
- high and low respectively
- low and high respectively
- equal in both cases
- none of the above
Answer
a. high and low respectively
When a vibrating object moves forward in air as medium, it pushes and compresses the air in front of it creating a region of high pressure. This region is called a compression.
When a vibrating object moves backward in air as medium, it creates a region of low pressure. This region is called a rarefaction.
Stethoscope work on the principle of
- Ultrasound
- multiple reflections of sound
- both (a) and (b)
- None of the above
Answer
b. multiple reflection of sound
Add stethoscope reflection image
