What is Sound? Sound is defined as the vibrations that travel through the air or another medium and can be heard when they reach a person's or animal's ear. Fact: Light travels faster than sound. Sound is produced by continuous and regular vibrations, in contrast to noise. In terms of physics, sound is a vibration that typically propagates as an audible wave of pressure, through a transmission medium such as a gas, liquid or solid. Fact: Sound requires a medium to propagate. Sound Quiz lists some of the important questions for competitive exams from the topic Sound and its characteristics.
Quick Facts: Humans can only hear sound waves as distinct pitches when the frequency lies between about 20 Hz and 20 kHz. Sound waves above 20 kHz are known as ultrasound and is not perceptible by humans. Sound waves below 20 Hz are known as infrasonic. Different animal species have varying hearing ranges.
Characteristics of Sound: Sound wave can be described by five characteristics: Wavelength, Amplitude, Time-Period, Frequency and Velocity or Speed. The decibel ( dB) is used to measure sound level.

Sound Quiz - Important General Science Questions
1. Ultrasonic waves have frequency (a) below 20 Hz (b) between 20 and 20,000 Hz (c) only above 20,000 Hz (d) only above 20,000 MHz Ans:C
2. Voice of your friend can be recognized by its (a) pitch (b) quality (c) intensity (d) velocity Ans:B
3. The ratio of the speed of a body to the speed of sound is called (a) Sonic index (b) Doppler ratio (c) Mach number (d) Refractive index Ans:C
4. The velocity of sound is largest in (a) water (b) air (c) metal (d) vacuum Ans:C
5. An underwater explosion is caused near the sea-shore. There are two observers, X under water and Y on land, each at a distance of 1 km from the point of explosion then (a) X will hear the sound earlier (b) Y will hear the sound earlier (c) Both will hear the sound at the same time (d) Y will not hear the sound at all Ans:A
6. If you are at open-air concert and someone’s head gets between you and the orchestra, you can still hear theorchestra because (a) sound waves pass easily through a head (b) a head is not very large compared with the wavelength of the sound (c) the sound is reflected from the head (d) the wavelength of the sound is much smaller than the head Ans:B
7. A thunder clap is heard 5.5 second after the lightening flash.The distance of the flash is (velocity of sound in air = 330 m/s) (a) 1780 m (b) 1815 m (c) 300 m (d) 3560 m Ans:B
8. Which of the following is carried by the waves from one place to another ? (a) Mass (b) Velocity (c) Wavelength (d) Energy Ans:D
9. Human ears can sense sound waves travelling in air having wavelength of (a) [latex]10^{–3} m[/latex] (b) [latex]10^{–2} m[/latex] (c) 1 (d) [latex]10^2 m[/latex] Ans:C
10. The frequency of a wave travelling at a speed of 500 ms–1 is 25Hz. Its time period is (a) 20 s (b) 0.05 s (c) 25 s (d) 0.04 s Ans:D
11. The velocity of sound in any gas depends upon (a) wavelength of sound only (b) density and elasticity of gas (c) intensity of sound waves only (d) amplitude and frequency of sound Ans:B
12. What is the effect of humidity on sound waves when humidity increases? (a) Speed of sound waves is more (b) Speed of sound waves is less (c) Speed of sound waves remains same (d) Speed of sound waves becomes zero Ans:A
13. Which of the following is used to find the depth of sea? (a) RADAR (b) SONAR (c) ECHO (d) None of these Ans:B
14. Echo is a type of (a) reflected sound (b) refracted sound (c) neither reflected sound nor refracted sound (d) None of these Ans:A
15. A shrill sound has a ______ pitch and a dull sound has a_____ pitch. (a) high, low (b) low, high (c) low, low (d) high, high Ans:A
16. _____ is the characteristic of a musical sound by which a loud sound can be distinguished from a faint sound even though both have the same pitch. (a) Loundness (b) Pitch (c) Quality (d) None of these Ans:A
17. If you go on increasing the stretching force on a wire in a guitar, its frequency. (a) increases (b) decreases (c) remains unchanged (d) None of these Ans:A
18. A vibrating body (a) will always produce sound (b) may or may not produce sound if the amplitude of vibration is low (c) will produce sound which depends upon frequency (d) None of these Ans:C
19. The wavelength of infrasonics in air is of the order of (a) [latex]10^0 m[/latex] (b) [latex]10^1 m[/latex] (c) [latex]10^{-1} m[/latex] (d) [latex]10^{-2} m[/latex] Ans:B
20. When a sound wave goes from one medium to another, the quantity that remains unchanged is (a) frequency (b) amplitude (c) wavelength (d) speed Ans:A
21. Resonance is an example of (a) tuning fork (b) forced vibration (c) free vibration (d) damped vibration Ans:B
22. A hollow sphere is filled with water. It is hung by a long thread. As the water flows out of a hole at the bottom, the period of oscillation will (a) first increase and then decrease (b) first decrease and then increase (c) go on increasing (d) go on decreasing Ans:A
23. If a tunnel is dug along the diameter of earth and a piece of stone is dropped into it, then the stone will (a) come out of the another end of the earth and will escape out in space (b) come to rest at the centre of the earth (c) start oscillating about the centre of the earth (d) stop at another end of the earth Ans:C
24. Which of the following statements is incorrect regarding the time period of a simple pendulum oscillating with small amplitude? The time period of the pendulum (a) is inversely proportional to [latex]\sqrt{g}[/latex] (b) is directly proportional to [latex]\sqrt{l}[/latex] (c) does not depend upon the amplitude (d) depends upon its mass, material and shape Ans:D
25. Range of audio-frequencies is (a) 1 – 15 Hz (b) 20 – 20, 000 Hz (c) [latex]10^3[/latex] [latex]- 10^5[/latex] Hz (d) [latex]10^6[/latex] [latex]- 10^8[/latex] Hz Ans:B
26. The marching soldiers break steps while crossing a bridge because of (a) damped oscillations (b) resonance (c) echo (d) reverberation Ans:B