The Loudness

Q.

Which property of sound is related to the degree of sensation of sound in the ear.

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.

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. Spherical sound waves are emitted uniformly in all directions from a point source. The variation in sound level SL as a function of distance ‘r’ from the source can be written as
Where a and b are positive constants.

1. $SL=-blog{r}^a$
2. $SL=a-b(logr{)}^2$
3. $SL=a-blogr$
4. $SL=\frac{a-b}{r^2}$

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

1. Displacement Amplitude
2. Pressure amplitude

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.

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 sound level at a point is increased by 30 dB. By what factor is the pressure amplitude increased?

1. 30

2. In 30

3. 32

4. 3

Q. Rahul is playing the drums. An increase in which of the following properties of the sound produced would result in an increase in loudness?

1. Amplitude
2. Speed
3. Pitch
4. Quality

Q. Due to a point isotropic sonic source, loudness at a point is L = 60 dB. If density of air is $\rho =\left(\frac{15}{11}\right)kg/m^3$ and velocity of sound in air is v = 330 m/s, the pressure oscillation amplitude at the point of observation is $[I_0={10}^{-12}W/m^2]$

1. $0.3N/m^2$
2. $0.03N/m^2$
3. $3\times {10}^{-3}N/m^2$
4. $3\times {10}^{-4}N/m^2$

Q. Sound with intensity larger than 120 dB appears painful to a person. A small speaker delivers 2.0 W of audio output. How close can the person get to the speaker without hurting his ears?

1. 40 cm

2. 80 cm

3. 120 cm

4. 10 cm