In one observation, the sound wave had a frequency of 1665 Hz and a pressure amplitude of 1 . 13 × 10 - 3 Pa . What were the displacement amplitude and (Given: Density of air = ρ air = 1 . 21 kg / m 3 )

Given that, The frequency of the sound wave = 1665 H z A pressure amplitude = 1 . 13 × 10 - 3 P a And, the density of air = 1 . 21 kg / m 3 Now, the relation between pressure amplitude and displacement amplitude is given as, Δ p max = B A k ∆ p m a x = v 2 ρ A ω v So, it can be written as, ∆ p m a x = v 2 ρ A 2 π f v Since the displacement amplitude is A = Δ p max 2 π f ρ v Therefore, A = 1 . 13 × 10 - 3 Pa 2 π ( 1665 Hz ) 1 . 21 kg / m 3 ( 343 m / s ) ⇒ A = 0 . 26 × 10 - 9 m ⇒ A = 0 . 26 nm Hence, the displacement amplitude is 0 . 26 nm .

In one observation, the sound wave had a frequency of 1665 Hz and a pressure amplitude of 1 . 13 × 10 - 3 Pa . What were the displacement amplitude and (Given: Density of air = ρ air = 1 . 21 kg / m 3 )

Given that, The frequency of the sound wave = 1665 H z A pressure amplitude = 1 . 13 × 10 - 3 P a And, the density of air = 1 . 21 kg / m 3 Now, the relation between pressure amplitude and displacement amplitude is given as, Δ p max = B A k ∆ p m a x = v 2 ρ A ω v So, it can be written as, ∆ p m a x = v 2 ρ A 2 π f v Since the displacement amplitude is A = Δ p max 2 π f ρ v Therefore, A = 1 . 13 × 10 - 3 Pa 2 π ( 1665 Hz ) 1 . 21 kg / m 3 ( 343 m / s ) ⇒ A = 0 . 26 × 10 - 9 m ⇒ A = 0 . 26 nm Hence, the displacement amplitude is 0 . 26 nm .

In one observation, the sound wave had a frequency of 1665 Hz and a pressure amplitude of 1 . 13 × 10 - 3 Pa . What were the intensity of the wave emitted by the ear? (Given: Density of air = ρ air = 1 . 21 kg / m 3 )

Given that, The frequency of the sound wave = 1665 H z A pressure amplitude = 1 . 13 × 10 - 3 P a And, the density of air = 1 . 21 kg / m 3 Now, the relation between pressure amplitude and displacement amplitude is given as, Δ p max = B A k But, the intensity of the wave in terms of the pressure amplitude is given by, I = Δ p m 2 2 ρ v Therefore, I = 1 . 13 × 10 - 3 Pa 2 2 1 . 21 kg / m 3 ( 343 m / s ) ⇒ I = 1 . 5 nW / m 2 Hence, the intensity of the wave emitted by the ear is 1 . 5 nW / m 2

Two loudspeakers M and N are located 20 m apart and emit sound at frequencies 118 Hz and 121 Hz , respectively. A car is initially at a point P , 1800 m away from the midpoint Q of the line M N and moves towards Q constantly at 60 km h - 1 along the perpendicular bisector of M N . It crosses Q and eventually reaches a point R , 1800 m away from Q . Let ν t represent the beat frequency measured by a person sitting in the car at time t . Let ν p , ν Q and ν R be the beat frequencies measured at locations P , Q and R , respectively. The speed of sound in air is 330 m s - 1 . Which of the following statement(s) is (are) true regarding the sound heard by the person?

The plot below represents schematically the variations of beat frequency with time

Two vehicles, each moving with speed u on the same horizontal straight road, are approaching each other. The wind blows along the road with velocity w . One of these vehicles blows a whistle of frequency f 1 . An observer in the other vehicle hears the frequency of the whistle to be f 2 . The speed of sound in still air is v . The correct statement (s) is (are):

If the wind blows from the source to the observer, f 2 > f 1 .

If the wind blows from the observer to the source, f 2 < f 1 .

If the wind blows from the source to the observer, f 2 < f 1 .

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IMPORTANT

Earn 100

In one observation, the sound wave had a frequency of $1665 Hz$ and a pressure amplitude of $1.13 \times 10^{- 3} Pa$ . What were

the displacement amplitude and

(Given: Density of air $= ρ_{air} = 1.21 kg / m^{3}$ )

Important Questions on Sound Waves and Doppler Effect

MEDIUM

Physics

IMPORTANT

PHYSICS FOR JOINT ENTRANCE EXAMINATION WAVES AND THERMODYNAMICS>Chapter 8 - Sound Waves and Doppler Effect>ILLUSTRATIONS>Q 8.13

In one observation, the sound wave had a frequency of $1665 Hz$ and a pressure amplitude of $1.13 \times 10^{- 3} Pa$ . What were

the intensity of the wave emitted by the ear?

(Given: Density of air $= ρ_{air} = 1.21 kg / m^{3}$ )

MEDIUM

Physics

IMPORTANT

PHYSICS FOR JOINT ENTRANCE EXAMINATION WAVES AND THERMODYNAMICS>Chapter 8 - Sound Waves and Doppler Effect>ILLUSTRATIONS>Q 8.14

A certain loudspeaker system emits sound isotropically with a frequency of $2000 Hz$ and an intensity of $1.0 mW / m^{2}$ at a distance of $6.0 m$ . Assume that there are no reflections,
What is the intensity at $30.0 m ?$ At $6.10 m,$ what are

Given: Density of air, $ρ = 1.21 kg / m^{3}$

MEDIUM

Physics

IMPORTANT

PHYSICS FOR JOINT ENTRANCE EXAMINATION WAVES AND THERMODYNAMICS>Chapter 8 - Sound Waves and Doppler Effect>ILLUSTRATIONS>Q 8.14

A certain loudspeaker system emits sound isotropically with a frequency of $2000 Hz$ and an intensity of $1.0 mW / m^{2}$ at a distance of $6.0 m$ . Assume that there are no reflections,

the displacement amplitude and

Given: Density of air, $ρ = 1.21 kg / m^{3}$

MEDIUM

Physics

IMPORTANT

PHYSICS FOR JOINT ENTRANCE EXAMINATION WAVES AND THERMODYNAMICS>Chapter 8 - Sound Waves and Doppler Effect>ILLUSTRATIONS>Q 8.14

A certain loudspeaker system emits sound isotropically with a frequency of $2000 Hz$ and an intensity of $1.0 mW / m^{2}$ at a distance of $6.0 m$ . Assume that there are no reflections,

the pressure amplitude?

Given: Density of air, $ρ = 1.21 kg / m^{3}$

HARD

Physics

IMPORTANT

PHYSICS FOR JOINT ENTRANCE EXAMINATION WAVES AND THERMODYNAMICS>Chapter 8 - Sound Waves and Doppler Effect>ILLUSTRATIONS>Q 8.15

A point sound source is situated in a medium of bulk modulus $1.6 \times 10^{5} N m^{- 2}$ . An observer standing at a distance $10 m$ from the source writes down the equation for the wave as $y = A \sin (15 π x - 6000 π t)$ . Here, $y$ and $x$ are in metres and $t$ is in second. The maximum pressure amplitude received to the observer's ear is $24 π Pa$ , then find the power of the sound source.

HARD

Physics

IMPORTANT

PHYSICS FOR JOINT ENTRANCE EXAMINATION WAVES AND THERMODYNAMICS>Chapter 8 - Sound Waves and Doppler Effect>ILLUSTRATIONS>Q 8.15

A point sound source is situated in a medium of the bulk modulus

1.6 \times 10^{5} N m^{- 2}

. An observer standing at a distance

10 m

from the source writes down the equation for the wave as

y = A \sin (15 π x - 6000 π t)

. Here,

y

and

x

are in metres and

t

is in second. The maximum pressure amplitude received to the observer's ear is

(24 π) Pa

, then find.
(a) the density of the medium,
(b) the displacement amplitude

A

of the waves received by the observer and
(c) the power of the sound source.

MEDIUM

Physics

IMPORTANT

PHYSICS FOR JOINT ENTRANCE EXAMINATION WAVES AND THERMODYNAMICS>Chapter 8 - Sound Waves and Doppler Effect>ILLUSTRATIONS>Q 8.16

If two sound waves, one in air and one in (fresh) water, are equal in intensity and angular frequency, what is the ratio of the pressure amplitude of the wave in water to that of the wave in air? Assume the water and the air are at $20 ° C$ .

(Given: Density of air $ρ_{air} = 1.20 kg / m^{3}$ Density of water $ρ_{water} = 1000 kg / m^{3}$ ,velocity of sound in air $v_{air} = 350 m / s$
and velocity of sound in water $v_{water} = 1512 m / s$ )

MEDIUM

Physics

IMPORTANT

PHYSICS FOR JOINT ENTRANCE EXAMINATION WAVES AND THERMODYNAMICS>Chapter 8 - Sound Waves and Doppler Effect>ILLUSTRATIONS>Q 8.16

If the pressure amplitudes are equal instead, what is the ratio of the intensities of the waves?

In one observation, the sound wave had a frequency of 1665 Hz and a pressure amplitude of 1.13×10-3 Pa. What were the displacement amplitude and (Given: Density of air =ρair=1.21 kg/m3)

Important Questions on Sound Waves and Doppler Effect

Learn and Prepare for any exam you want !

In one observation, the sound wave had a frequency of $1665 Hz$ and a pressure amplitude of $1.13 \times 10^{- 3} Pa$ . What were

the displacement amplitude and

(Given: Density of air $= ρ_{air} = 1.21 kg / m^{3}$ )