Decibels

Q.

Intensity level of a sound of intensity I is 30 dB. The ratio $\frac{I}{I_0}$ is (Where $I_0$

is the threshold of hearing)

1. 3000

2. 1000

3. 300

4. 30

Q.

A pupil determines the velocity of sound as 330 m/s. If the actual velocity of sound is 332 m/s. Calculate the percentage error.

Q. an object is performing damped oscillations . a force of magnitude F=F cos(wt) is applied on the object . Displacement amplitude is maximum when (1)w is slightly greater than natural frequency (2)w is slightly lesser than natural frequency (3)w is equal to natural frequency (4)all of these

Q. explain loudness versus intensity of sound graph in detai

Q. We know that L=K log10 l, where L is loudness and l is intensity. What is K then?

Q. Find the amplitude of motion of the air in the path of a $40\text{dB},1000\text{Hz}$ sound wave.
[Assume that the density of air is $1.3{\text{kg/m}}^3$ and speed of sound in $340\text{m/s}$].

1. $1\text{cm}$
2. $1\mu \text{m}$
3. $1\text{nm}$
4. $1\text{mm}$

Q. What is the intensity of sound of 100dB?

Q. A two-fold increase in intensity of a wave implies an increase of (Given: ${\text{log}}_{10}2=0.3010$)

1. $2\text{dB}$
2. $10\text{dB}$
3. $3.01\text{dB}$
4. $0.5\text{dB}$

Q. The ratio of intensities between two coherent sound sources is $9:1$. The difference of loudness in decibels $\left(\text{dB}\right)$ between maximum and minimum intensities when they interfere in space is

1. $10\log 4$
2. $10\log 9$
3. $10\log 3$
4. $\log 3$

Q. If the intensity of sound is doubled, by how many decibels does the sound level increase?

Q. ntA sound absorber attenuates the sound level by 20 dB.The intensity decreases by a factor ofn nta)1000n ntb)10000n ntc)10n ntd)100n