The Loudness

Q.

A vibrating tuning fork is placed over the mouth of a burette filled with water. The tap is opened and the water level gradually falls. It is observed that the sound becomes the loudest for a particular length of the air column.

Q.

You live on a busy street, but as a music lover, you want to reduce the traffic noise. If you install special sound-reflecting windows that reduce the sound intensity level (in dB) by 30 dB, by what fraction have you lowered the sound intensity $\left(in\frac{w}{m^2}\right)$?

1. ${10}^{-3}$

2. ${10}^{-1}$

3. $\frac{1}{2}$

4. ${10}^{-4}$

Q. The intensity level $1\text{m}$ away from a point source is $40\text{dB}$. Threshold intensity of hearing is ${10}^{-12}{\text{W/m}}^2$. If there is no loss of power in air, then intensity level at $10\text{m}$ from the source is

1. $30\text{dB}$
2. $10\text{dB}$
3. $20\text{dB}$
4. $40\text{dB}$

Q. If the intensity is increased by a factor $x$, sound level is increased by $20\text{dB}$. Then, the value of $x$ is

Q. If the sound level in a room is increased from 50 dB to 60 dB, by what factor is the pressure amplitude increased?

1. $\sqrt{10}$

2. 10

3. 2

4. None of these

Q. Which parameter has a more direct influence on the loudness of a sound wave?

1. Displacement Amplitude
2. Pressure amplitude

Q. A point source emits sound waves of constant power with intensity inversely proportional to the square of the distance from the source. By how many decibels does the sound loudness drop, when you move from point $A$ to $B$ ? Distance of $B$ from the source is two times the distance of $A$ from the source. [Take ${\log }_{10}2=0.3$ ]

1. $4\text{dB}$
2. $2\text{dB}$
3. $6\text{dB}$
4. $8\text{dB}$

Q.

What is loudness of sound? On what factors do it depend?