Mock Test

Sound

by Anish
Updated On:

Sound

Total Questions: 56

11. In the context of permissible noise of levels match list-i with list-ii and select the answer from the code given below the lists. [U.P.P.C.S.(pre) 2022]

 

List-1(area)List-1(permissible noise level)
(a) residential1. 50 dB
(b) silent zone2. 55 dB
(c) industrial3. 65 dB
(d) commercial4. 70 dB

code :

-ABCD
(a)3421
(b)1234
(c)2134
(d)2143

 

Correct Answer: (d)
Solution:As per the noise pollution rules 2000 of India ambient air quality standard in respect of noise (permissible noise levels) in given areas are as follows :
Area

permissible noise level (dB)

 daytime

permissible noise level (dB)

 night time

residential5545
silent zone5040
industrial7570
commercial6555

12. The tolerable limit of noise for human being is around : [R.A.S/R.T.S (PRE) 1993]

Correct Answer: (b) 85 decibel
Solution:The intensity of sound in normal conversation is 30-60 decibel. The sound of 50 decibel is enough to wake up a sleeping person to remain continuously in the sound of 80 decibel proves to be harmful 90 decibel is the maximum limit to tolerate any noise by human being .

13. Sound above what level is considered hazardous noise pollution ? [U.P.P.C.S. (pre) 2013, U.P.P.C.S.(MAINS) 2008]

Correct Answer: (c) 80 dB
Solution:Sound above the 80 decibel is considered the hazardous noise pollution continued exposure to high levels of noise results in fatigue hearing loss or even total loss of hearing changes in blood circulation changes in breathing patterns etc.

14. Which one of the following units is used for measurement of noise pollution ? [U.P.P.C.S.(MAINS) 2017]

Correct Answer: (b) decibel
Solution:Sound above the 80 decibel is considered the hazardous noise pollution continued exposure to high levels of noise results in fatigue hearing loss or even total loss of hearing changes in blood circulation changes in breathing patterns etc.

15. The optimum sound level for human beings is - [R.A.S/R.T.S.(PRE) 2012]

Correct Answer: (b) 60 dB
Solution:The average sound level in normal conversation is 60 decibel it is appropriate for human ears. The sound of higher than the 80 dB can cause damage to the ear cells .

16. Loudness of sound is measured in terms of following : [U.P.R.O/A.R.O.(MAINS) 2017]

Correct Answer: (b) amplitude
Solution:The amplitude of a wave is related to the amount of energy it carries. A high amplitude wave carries a large amount of energy, a low amplitude wave carries a small amount of energy. The average amount of energy passing through a unit area per unit of time in a specified direction is called the intensity of the wave.

As the amplitude of the sound wave increases, the intensity of sound increases. Sounds with higher intensity are perceived to be louder. Relative sound intensities are often given in units named decibel (dB).

17. A worker was working on the rail track. A boy at a distance holds his ear near the rail track. This boy was able to hear sound of the blow of workman twice. It is because of: [R.A.S/R.T.S (PRE) 1994-95]

Correct Answer: (a) The speed of sound is greater in steel than in air.
Solution:The speed of sound is greater in steel than in air, as sound reaches first by rail track and then by air. Therefore the boy hears the sound twice.

18. Which of the following statements is/are true in relation to sound waves? [Chhattisgarh P.C.S. (Pre) 2020]

Statement I: Speed of sound decreases when we go from solid to gaseous state
Statement II: In any medium as we decrease the temperature, the speed of sound increases Statement III: Speed of sound is less in aluminium medium than in glass medium.

Correct Answer: (c) Only Statement I is true.
Solution:The Speed of sound depends upon the nature of medium through which it propagates. Speed of sound is maximum in solids while minimum in gases. Speed of sound is less in glass medium than in aluminium medium. Increase in temperature results to increase in the speed of sound in any medium. Hence, among the given statement, only statement I is true.

19. When a sound wave goes from one medium to another, the quantity that remains unchanged is: [66th B.P.S.C. (PRE)(RE.EXAM) 2020]

Correct Answer: (a) Frequency
Solution:When a sound wave goes from one medium to another medium its frequency usually remains the same  because it is like a driven oscillation and maintain the frequency of the original source while its speed and wavelength are changed the amplitude of sound is also changed as it decrease with distance from its source.

20. Before playing the orchestra in a musical concert a sitarist tries to adjust the tension and pluck the string suitably by doing so he /she us adjusting : [68th B.P.S.C. (PRE) 2022]

Correct Answer: (a) frequency of the sitar string with the frequency of other musical instruments.
Solution:String length diameter density and tension determination the frequency in which it will vibrate.

Since the other three are fixed it is the tension that sitarist tries to adjust to tune its natural frequency and while playing the sitar he changed the effective length of the string by touching the string at different point of the finger this is how we get different melodious notes .

Amplitude /intensity of sound is not determined by the tension in the string since it depends on how produce low or very high sound and that's why he has to adjust the tension beforehand so the correct answer is (a).

Anish

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