Question

In India permissible ambient noise level for residential area during night is
A)65 db
B)55db
C)45db
D)40db

Answer 1

As per law and standards, the noise level in silence zones should not be more than 40 db at night. Frequency shows the rate of vibration of medium particles and the number of waves passing per second. Pitch is the sensation of frequency. The measure of the loudness or softness of a sound is determined by its amplitude. The amplitude of the sound waves is usually dependent on the force with which an object is made to vibrate.

Complete answer:
Children that are present beyond the age of five and some animals, such as dogs can hear up to 25 kHz (1 kHz = 1000 Hz). As with time when people become older their ears become less sensitive to higher frequencies.
Sounds of frequencies below 50 Hz are called infrasonic sound or infrasound. If human beings could have heard infrasound, we would hear the vibrations of a pendulum just as we hear the vibrations of the wings of a bee.

According to the standards the decibel level is set as 50 db in silence zones during day times. But somehow it varied from 56 db to 77 db at day time and 51 db to 75 db at night. Construction work and noise pollution done by vehicles disturbs the peaceful environment of residential areas. It causes many discomforts and problems related to mental disturbance to patients in hospitals. Not only in hospitals but noise pollution causes distractions and annoyance in institutional areas also. Thus, as per law and standards, 55 db is a limit set for residential areas in day-time and 45 db at night time.

Hence, the correct answer is option (C)

Note: It should be the duty of every citizen to reduce noise pollution so that it would not cause any discomfort to the people nearby. Continuously listening to a high volume of sound can damage hearing.