Answers of Quiz 1740 (Sound)

1. Sound is a kind of energy, it is produced by vibration.
2. Acoustics
3. Vibration means one complete round trip of the body.
4. Back & forth movement (as in pendulum) is called Oscillation.
5. Wavelength is the distance measured in the direction of propagation of a wave between two successive points in the wave. Wavelength = v/f
6. Frequency is the number of waves generated by a source in one second. f = 1/T
7. Time Period is the time required to complete one vibration or oscillation. T = 1/f
8. Amplitude is the maximum displacement of the body on either side of its equilibrium position. A = D/F
9. Reflection of sound is called Echo.
10. Pitch is that property of sound which enables us to distinguish between a shrill & a flat sound. Pitch of a sound depends upon the frequency of sound. The greater the frequency the higher the pitch.
11. The unpleasant sound is called Noise.
12. The pleasant sound is called Music.
13. White Noise is the random noise spread evenly across all frequencies.
14. Noise Pollution is the disturbing or excessive noise that may harm the activity or balance of human.
15. Simple Harmonic Motion (SHM) is a type of periodic motion where the restoring force is directly proportional to the displacement & acts in the direction opposite to that of displacement.
16. Ultrasound is a type of imaging. It uses high-frequency sound waves to look at organs & structures inside the body.
17. Recorded, transmitted, or reproduced sound
18. 343 metre per second
19. Between 20 to 20,000 Hz
20. By vibration
21. Sound waves need to travel through a medium. The sound waves move through medium by vibrating the molecules in the matter.
22. (a) Hot air
23. (d) Vacuum
24. Because speed of light is faster
25. Because there is no medium in space
26. Ultrasonics