Intensity and Loudness of Sound

Select the loudness of whisper.

If pressure amplitude in a sound wave is changed from $P_o$ to $3P_o$. The percentage increase in the intensity of wave is

Select the correct statment about the two mechanical waves, $y_1=2 \sin 2\mathrm{\pi } \left(50\mathrm{t}-2\mathrm{x}\right)$ and $y_2=4\sin 2\mathrm{\pi } \left(\mathrm{ax} +100 \mathrm{t}\right)$, propagate in a medium with the same speed. 

How much intense is $80 dB$ sound in comparison to $40 dB?$

A hearing test is conducted on an aged person. It is found that her threshold of hearing is $20 \mathrm{dB}$ at $1 \mathrm{kHz}$, and it rises linearly with frequency to, $60 \mathrm{dB}$ at, $9 \mathrm{kHz}$. The minimum intensity of sound that the person can hear at, $5 \mathrm{kHz}$ is,

The intensity of sound during the festival season increased by, $100$ times. This could imply a decibel level rise from-

If the intensity is increased by a factor of $20$, then how many decibels in the sound level increased?

Two loudspeakers are being compared. One is perceived to be $32$ times louder than the other. The difference in intensity levels between the two, when measured in decibels, is

(Note: Human mind perceives doubling of loudness for each $10 \mathrm{dB}$ change)

The intensity ratio of two waves is $1:9$. The ratio of their amplitudes is___

Statement I- Two longitudinal waves given by equation $y_1\left(x,t\right)=2a\sin (\omega t-kx)$ and $y_2\left(x,t\right)=a\sin \left(2\omega t-2kx\right)$ will have equal intensity.

Statement II- Intensity of waves of given frequency in same medium is proportional to square of amplitude only

Two radio station broadcast their programmes at the same amplitude $A$ and at slightly different frequency ${\omega }_1$ and ${\omega }_2$ respectively where ${\omega }_2-{\omega }_1={10}^3 \mathrm{H}\mathrm{z}$. A detector is receiving signals from the two stations simultaneously. It can only detect signals of intensity $2A^2$. The time interval between successive maxima of the intensity of the signal received by the detector is

Two identical sound $A$ and $B$ reach a point in the same phase. The resultant sound is $C$. The loudness of $C$ is $n \mathrm{dB}$ higher the loudness of $A$.

A sound absorber attenuates the sound level by $20 \mathrm{dB}$. The intensity decreases by a factor of

The ratio of intensities between two coherent sound sources is $4 :1$. The difference of loudness in decibels $\left(\mathrm{d}\mathrm{B}\right)$ between maximum and minimum intensities, on their interference in space is

How many times more intense is a $60 \mathrm{dB}$ sound than a $30 \mathrm{dB}$ sound?

In a stationary wave represented by $y=2a\cos \left(kx\right)\sin \left(\omega t\right)$ the intensity at a certain point is maximum when

A point source emits sound equally in all directions in a non-absorbing medium. Two points P and Q are at distance of 2m and 3m respectively from the source. The ratio of the intensities of the waves at P and Q is

In Quincke's tube a detector detects minimum intensity. Now one of the tube is displaced by 5 cm. During displacement detector detects maximum intensity 10 times, then finally a minimum intensity (when displacement is complete). The wavelength of sound is :

In a test of subsonic Jet flies over head at an altitude of 100 m. The sound intensity on the ground as the Jet passes overhead is 160 dB. At what altitude should the plane fly so that the ground noise is not greater than 120 dB.