Questions:

1. Sound loudness is measured using its power. Specifically, _______ measures the relative difference between one power level and a reference level on a base-10 logarithmic scale. Fill in the blank.

2. The reference level in the question above relates to the threshold of human hearing. In general, this is the minimum level of sound that an organism can hear with no other source of noise nearby. What is the threshold for humans (in pascals)?

3. The human ear isn’t equally sensitive to all frequencies of sound. So scientists modify a measured sound power level by a factor derived from the _-_________ scale, first published in 1933. Fill in the blanks.

4. When an object produces a fluctuating amount of sound over time, the equivalent sound level (L_eq) denotes the amount of acoustic energy averaged over that time. What is L_eq called when sound data is collected at narrow intervals (fractions of a second)?

5. India’s Noise Pollution (Regulation and Control) Rules 2000 specify environmental noise limits by area and time of day. In residential areas, the maximum allowable noise between 6 am and 10 pm is X dB(A) L_eq. What is the value of X?

Answers:

1. Decibel

2. Neper

3. 20 micropascals

4. Short L_eq

5. 55 dB(A) L_eq