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All questions of Wave Motion and Sound wave for JEE Exam
A sound source of frequency 600 Hz is moving towards an observer with velocity 20m/s. The speed of sound is 340m/s. The frequency heard by observer will be- a)630.5hz
- b)30hz
- c)637.5hz
- d)63.5 Hz
Correct answer is option 'C'. Can you explain this answer?
A sound source of frequency 600 Hz is moving towards an observer with velocity 20m/s. The speed of sound is 340m/s. The frequency heard by observer will be
a)
630.5hz
b)
30hz
c)
637.5hz
d)
63.5 Hz
|
Preeti Khanna answered |
F(s)/F(l) = [V+V(s)]/[V+V(l)]
V = velocity of sound = 340m/s
V(l) = velocity of listener = 0
F(l) = frequency heard by listener = ?
V(s) = velocity of source = -20m/s (because, it's source to listener)
F(s) = frequency of source = 600hz
By putting these values in the above formula and solving we get,
F(l) = 637.5 Hz.
Hence C is correct.
V = velocity of sound = 340m/s
V(l) = velocity of listener = 0
F(l) = frequency heard by listener = ?
V(s) = velocity of source = -20m/s (because, it's source to listener)
F(s) = frequency of source = 600hz
By putting these values in the above formula and solving we get,
F(l) = 637.5 Hz.
Hence C is correct.
As a wave propagates; which of the following is not satisfied?- a)the wave intensity remains constant for a plane wave
- b)total intensity of the spherical wave over the spherical surface centered at the source remains constant at all times
- c)the wave intensity decreases as the inverse of the square of the distance from the source for a spherical wave
- d)the wave intensity decreases as the inverse of the distance from the source for a spherical wave
Correct answer is option 'D'. Can you explain this answer?
As a wave propagates; which of the following is not satisfied?
a)
the wave intensity remains constant for a plane wave
b)
total intensity of the spherical wave over the spherical surface centered at the source remains constant at all times
c)
the wave intensity decreases as the inverse of the square of the distance from the source for a spherical wave
d)
the wave intensity decreases as the inverse of the distance from the source for a spherical wave
|
|
Parnas Vyas answered |
Intensity is in inverse proportion to surface area of the imaginary sphere at any point.
where A=4πr^2
so inverse of distance(r, radius) is incorrect.
where A=4πr^2
so inverse of distance(r, radius) is incorrect.
A cylindrical tube, open at both ends, has a fundamental frequency f in air. The tube is dipped vertically in water so that half of it is in water. The fundamental frequency of the air-column is now:- a)f/2
- b)f
- c)2f
- d)3f/2
Correct answer is option 'B'. Can you explain this answer?
A cylindrical tube, open at both ends, has a fundamental frequency f in air. The tube is dipped vertically in water so that half of it is in water. The fundamental frequency of the air-column is now:
a)
f/2
b)
f
c)
2f
d)
3f/2
|
Krishna Iyer answered |
As we know, f=v/2l
Now, it will act as one end and one end closed.
So, f0=v/2l’=v/4½=v/2l=f
Now, it will act as one end and one end closed.
So, f0=v/2l’=v/4½=v/2l=f
Pure sound notes from two sources make the molecules of air at a location vibrate simple harmonically in accordance with the equations.
y1 = 0.008 sin (604 n t) and
y2 = 0.007 sin (610 n t) respectively.
The number of beast heard by a person at the location will be:- a)3
- b)1
- c)2
- d)4
Correct answer is option 'A'. Can you explain this answer?
Pure sound notes from two sources make the molecules of air at a location vibrate simple harmonically in accordance with the equations.
y1 = 0.008 sin (604 n t) and
y2 = 0.007 sin (610 n t) respectively.
The number of beast heard by a person at the location will be:
y1 = 0.008 sin (604 n t) and
y2 = 0.007 sin (610 n t) respectively.
The number of beast heard by a person at the location will be:
a)
3
b)
1
c)
2
d)
4
|
Tarun Kaushik answered |
Given that two sources produce pure sound notes as follows: y1= 0.008 sin (604 n t) y2= 0.007 sin (610 n t) To find the number of beats heard by a person at the location, we need to first understand the concept of beats.
Beats: When two sound waves of slightly different frequencies are superimposed, we hear a periodic variation in the loudness of sound. This variation is called beats.
The number of beats heard per second is given by the difference between the frequencies of the two sound waves.
Mathematically, the beat frequency is given by fbeat = |f1 - f2| where f1 and f2 are the frequencies of the two sound waves. In this problem, the frequencies of the two sound waves are 604 n and 610 n, respectively.
Therefore, the beat frequency is fbeat = |604 n - 610 n| = 6 n Since the beat frequency is 6 n, the number of beats heard per second is 6. Since each beat corresponds to two sound waves (one from each source), the total number of sound waves heard per second is twice the number of beats, which is 12.
However, the question asks for the number of distinct sounds heard, which is equal to the number of beats. Therefore, the answer is 3 (Option A).
Phenomenon of beats is not used in- a)Tuning musical instruments
- b)Detecting the presence of dangerous gases in mines
- c)Designing low frequency oscillators
- d)Radars for detecting submarines
Correct answer is option 'D'. Can you explain this answer?
Phenomenon of beats is not used in
a)
Tuning musical instruments
b)
Detecting the presence of dangerous gases in mines
c)
Designing low frequency oscillators
d)
Radars for detecting submarines
|
Top Rankers answered |
Radar uses electromagnetic energy pulses. The radio-frequency (rf) energy is transmitted to and reflected from the reflecting object. A small portion of the reflected energy returns to the radar set. This returned energy is called an ECHO. Radar sets use the echo to determine the direction and distance of the reflecting object.
It does not work on phenomena of beats.
It does not work on phenomena of beats.
When two tuning forks are sounded together 4 beats are heard per second. One tuning fork is of frequency 346 Hz. When its prong is loaded with a little wax, the number of beats is increased to 6 per second. The frequency of the other fork is:- a)352 Hz
- b)340 Hz
- c)350 Hz
- d)342 Hz
Correct answer is option 'C'. Can you explain this answer?
When two tuning forks are sounded together 4 beats are heard per second. One tuning fork is of frequency 346 Hz. When its prong is loaded with a little wax, the number of beats is increased to 6 per second. The frequency of the other fork is:
a)
352 Hz
b)
340 Hz
c)
350 Hz
d)
342 Hz
|
Suresh Reddy answered |
Frequency of fork one is 346 Hz.
When the other fork is waxed, the beat is increased.
So, the frequency of other fork is less than the frequency of fork one.
So,
beat = frequency of fork one − frequency of second fork
4=346− Frequency of second fork
Frequency of second fork =350 Hz
When the other fork is waxed, the beat is increased.
So, the frequency of other fork is less than the frequency of fork one.
So,
beat = frequency of fork one − frequency of second fork
4=346− Frequency of second fork
Frequency of second fork =350 Hz
To the nearest order of magnitude, how many times greater than the speed of sound is the speed of light?- a)104
- b)1012
- c)108
- d)106
Correct answer is option 'D'. Can you explain this answer?
To the nearest order of magnitude, how many times greater than the speed of sound is the speed of light?
a)
104
b)
1012
c)
108
d)
106
|
Lavanya Menon answered |
Speed of sound in air is 343 m/s or we can say approx 300m/s
And speed of light is approx 300,000,000 m/s
Clearly the ratio is 106
And speed of light is approx 300,000,000 m/s
Clearly the ratio is 106
Fundamental note in open pipe (v1=ν/2L) has _________ the frequency of the fundamental note in closed organ pipe (v2=ν/4L).a)Twiceb)Halfc)Four timesd)ThriceCorrect answer is option 'A'. Can you explain this answer?
|
Riya Banerjee answered |
Let L be a length of the pipe,
The fundamental frequency of closed pipe is
v2=ν/4L .....(i)
where ν is the speed of sound in air.
Fundamental frequency of open pipe of same length is
v1=ν/2L .....(ii)
After dividing v1 with v2,
v1/v2= ν/2L/ ν/4L
v1=2v2
The fundamental frequency of closed pipe is
v2=ν/4L .....(i)
where ν is the speed of sound in air.
Fundamental frequency of open pipe of same length is
v1=ν/2L .....(ii)
After dividing v1 with v2,
v1/v2= ν/2L/ ν/4L
v1=2v2
In an experiment to find the speed of waves in a rope, a standing wave pattern is established as shown in diagram below. The vibrating end of rope makes 90 vibrations per minute. The speed of the waves is
- a)4 m/s
- b)3 m/s
- c)6 m/s
- d)2 m/s
Correct answer is 'C'. Can you explain this answer?
In an experiment to find the speed of waves in a rope, a standing wave pattern is established as shown in diagram below. The vibrating end of rope makes 90 vibrations per minute. The speed of the waves is
a)
4 m/s
b)
3 m/s
c)
6 m/s
d)
2 m/s
|
Anjana Sharma answered |
90 vibrations in 60 seconds mans _frequency, f =1.5Hz
According to diagram1.5 Hz is covered in 6m wavelength, ω = 4m
We have qmed ,v = f x ω = 1.5 x 4 = 6m/s
The necessary condition for phenomenon of interference to occur is- a)There should be two coherent sources.
- b)The frequency and amplitude of both the waves should be same
- c)The propagation of waves should be simultaneously and in same direction
- d)All of the above
Correct answer is option 'D'. Can you explain this answer?
The necessary condition for phenomenon of interference to occur is
a)
There should be two coherent sources.
b)
The frequency and amplitude of both the waves should be same
c)
The propagation of waves should be simultaneously and in same direction
d)
All of the above
|
Neha Joshi answered |
The necessary condition for phenomenon of interference to occur are:
1. There should be two coherent sources.
2. The frequency and amplitude of both the waves should be same.
3. The propagation of waves should be simultaneously and in same direction.
These are the conditions, no explanation.
1. There should be two coherent sources.
2. The frequency and amplitude of both the waves should be same.
3. The propagation of waves should be simultaneously and in same direction.
These are the conditions, no explanation.
Time interval between two successive maxima of sound waves with frequencies v1 and v2 is given by- a)v1/v2
- b)1/ (v1 - v2)
- c)v1 = v2 = 0
- d)v1 - v2
Correct answer is option 'B'. Can you explain this answer?
Time interval between two successive maxima of sound waves with frequencies v1 and v2 is given by
a)
v1/v2
b)
1/ (v1 - v2)
c)
v1 = v2 = 0
d)
v1 - v2
|
|
Nandini Iyer answered |
As we know time interval will have dimensions of time so check in option for dimension of time.
Dimensions of v is "per second" or [T-1]
Dimensions of v is "per second" or [T-1]
Waves associated with moving protons, electrons, neutrons, atoms are known as- a)none of these
- b)Gamma rays
- c)Matter waves
- d)Electromagnetic waves
Correct answer is option 'C'. Can you explain this answer?
Waves associated with moving protons, electrons, neutrons, atoms are known as
a)
none of these
b)
Gamma rays
c)
Matter waves
d)
Electromagnetic waves
|
|
Anjali Iyer answered |
Matter waves are a central part of the theory of quantum mechanics, being an example of wave–particle duality. All matter can exhibit wave-like behavior. For example, a beam of electrons can be diffracted just like a beam of light or a water wave.
If the source of sound moves at the same speed or faster than speed of the wave then it results in- a)Doppler effect
- b)Beats
- c)Shock waves
- d)Refraction of sound
Correct answer is option 'C'. Can you explain this answer?
If the source of sound moves at the same speed or faster than speed of the wave then it results in
a)
Doppler effect
b)
Beats
c)
Shock waves
d)
Refraction of sound
|
|
Lavanya Menon answered |
The Doppler Effect is observed whenever the speed of the source is moving slower than the speed of waves. But if the source actually moves at the same speed as or faster than the waves, a different phenomenon is observed. This phenomenon is known as Shock waves or Sonic Booms.
Two trains A and B approach a station from opposite sides, sounding their whistles. A stationary observer on the platform hears no beats. If the velocities of A and B are 15 m/s and 30 m/s respectively and the real frequency of the whistle of B is 600 Hz, the real frequency of the whistle of A is (Velocity of sound = 330 m/s).- a)660 Hz
- b)600 Hz
- c)570 Hz
- d)630 Hz
Correct answer is option 'D'. Can you explain this answer?
Two trains A and B approach a station from opposite sides, sounding their whistles. A stationary observer on the platform hears no beats. If the velocities of A and B are 15 m/s and 30 m/s respectively and the real frequency of the whistle of B is 600 Hz, the real frequency of the whistle of A is (Velocity of sound = 330 m/s).
a)
660 Hz
b)
600 Hz
c)
570 Hz
d)
630 Hz
|
|
Preeti Iyer answered |
When no beats is listened at the station thus we get the relative frequencies of both the trains are the same.
Hence the relative frequency of the train B is 600 (330/300) = 660
similarly the relative frequency of train A is f(330/315) = 660
Hence we get f = 630Hz
Hence the relative frequency of the train B is 600 (330/300) = 660
similarly the relative frequency of train A is f(330/315) = 660
Hence we get f = 630Hz
In Doppler effect change in frequency depends on- a)distance between source and listener
- b)speeds of source and listener
- c)density of air
- d)half of distance between source and listener
Correct answer is option 'B'. Can you explain this answer?
In Doppler effect change in frequency depends on
a)
distance between source and listener
b)
speeds of source and listener
c)
density of air
d)
half of distance between source and listener
|
Om Desai answered |
The reason for the Doppler effect is that when the source of the waves is moving towards the observer, each successive wave crest is emitted from a position closer to the observer than the crest of the previous wave.
Maximum destructive inference between two waves occurs when the waves are out of the phase by- a)π/2radians
- b)π radians
- c)π/3 radians
- d)π/4 radians
Correct answer is option 'B'. Can you explain this answer?
Maximum destructive inference between two waves occurs when the waves are out of the phase by
a)
π/2radians
b)
π radians
c)
π/3 radians
d)
π/4 radians
|
|
Anjali Iyer answered |
Destructive interference occurs when the maxima of two waves are 180 degrees out of phase: a positive displacement of one wave is cancelled exactly by a negative displacement of the other wave. The amplitude of the resulting wave is zero. ... The dark regions occur whenever the waves destructively interfere.
Two sound sources fixed at a given distance apart are emitting sound each of wavelength λ. A Listener moves with a velocity v0 along the line joining the two sources , the number of beats heard by him per second is- a)4v0/λ
- b)v0/3λ
- c)v0/2λ
- d)2v0/λ
Correct answer is option 'D'. Can you explain this answer?
Two sound sources fixed at a given distance apart are emitting sound each of wavelength λ. A Listener moves with a velocity v0 along the line joining the two sources , the number of beats heard by him per second is
a)
4v0/λ
b)
v0/3λ
c)
v0/2λ
d)
2v0/λ
|
Jasvir Special answered |
A
Two harmonic waves traveling on a string in the same direction both have a frequency of 100 Hz, a wavelenqth of 2.0cm, and amplitude of 0.020 m. In addition, they overlap each other. What is the amplitude of the resultant wave if the original waves differ in phase by Syntax error from line 1 column 49 to line 1 column 73. Unexpected ‘mathsize’./6?- a)3.5 cm
- b)4.2 cm
- c)3.7 cm
- d)3.9 cm
Correct answer is option 'D'. Can you explain this answer?
Two harmonic waves traveling on a string in the same direction both have a frequency of 100 Hz, a wavelenqth of 2.0cm, and amplitude of 0.020 m. In addition, they overlap each other. What is the amplitude of the resultant wave if the original waves differ in phase by Syntax error from line 1 column 49 to line 1 column 73. Unexpected ‘mathsize’./6?
a)
3.5 cm
b)
4.2 cm
c)
3.7 cm
d)
3.9 cm
|
|
Rajeev Nair answered |
Question:
Two harmonic waves traveling on a string in the same direction both have a frequency of 100 Hz, a wavelength of 2.0 cm, and amplitude of 0.020 m. In addition, they overlap each other. What is the amplitude of the resultant wave if the original waves differ in phase by 6π?
Solution:
Given parameters:
Frequency of each wave = 100 Hz
Wavelength of each wave = 2.0 cm
Amplitude of each wave = 0.020 m
Phase difference between the waves = 6π
To find: Amplitude of the resultant wave
We know that the displacement of a wave is given by the equation:
y = A sin(kx - ωt + φ)
where, A = amplitude of the wave, k = wave number, x = position, ω = angular frequency, t = time, and φ = phase constant.
For two waves with the same frequency and wavelength traveling in the same direction, the wave number and angular frequency are the same, and the displacement equation becomes:
y1 = A sin(kx - ωt + φ1)
y2 = A sin(kx - ωt + φ2)
where, φ1 and φ2 are the phase constants of the two waves.
The resultant wave is obtained by adding the two waves:
y = y1 + y2
= A sin(kx - ωt + φ1) + A sin(kx - ωt + φ2)
= 2A cos((φ1 - φ2)/2) sin(kx - ωt + (φ1 + φ2)/2)
where, cos((φ1 - φ2)/2) is the amplitude of the resultant wave.
Given that the phase difference between the waves is 6π, we have:
φ1 - φ2 = 6π
cos((φ1 - φ2)/2) = cos(3π) = -1
Substituting the given values, we get:
Amplitude of the resultant wave = 2(0.020) (-1) = -0.040 m
However, amplitude is always positive, so we take the absolute value:
Amplitude of the resultant wave = 0.040 m
Therefore, the amplitude of the resultant wave is 0.040 m.
Two harmonic waves traveling on a string in the same direction both have a frequency of 100 Hz, a wavelength of 2.0 cm, and amplitude of 0.020 m. In addition, they overlap each other. What is the amplitude of the resultant wave if the original waves differ in phase by 6π?
Solution:
Given parameters:
Frequency of each wave = 100 Hz
Wavelength of each wave = 2.0 cm
Amplitude of each wave = 0.020 m
Phase difference between the waves = 6π
To find: Amplitude of the resultant wave
We know that the displacement of a wave is given by the equation:
y = A sin(kx - ωt + φ)
where, A = amplitude of the wave, k = wave number, x = position, ω = angular frequency, t = time, and φ = phase constant.
For two waves with the same frequency and wavelength traveling in the same direction, the wave number and angular frequency are the same, and the displacement equation becomes:
y1 = A sin(kx - ωt + φ1)
y2 = A sin(kx - ωt + φ2)
where, φ1 and φ2 are the phase constants of the two waves.
The resultant wave is obtained by adding the two waves:
y = y1 + y2
= A sin(kx - ωt + φ1) + A sin(kx - ωt + φ2)
= 2A cos((φ1 - φ2)/2) sin(kx - ωt + (φ1 + φ2)/2)
where, cos((φ1 - φ2)/2) is the amplitude of the resultant wave.
Given that the phase difference between the waves is 6π, we have:
φ1 - φ2 = 6π
cos((φ1 - φ2)/2) = cos(3π) = -1
Substituting the given values, we get:
Amplitude of the resultant wave = 2(0.020) (-1) = -0.040 m
However, amplitude is always positive, so we take the absolute value:
Amplitude of the resultant wave = 0.040 m
Therefore, the amplitude of the resultant wave is 0.040 m.
If a source of sound was moving toward a receiver at 1/3 the speed of sound, what would the resulting wavelength be?- a)6 times the emitted wavelength
- b)2/3 of the emitted wavelength
- c)1/3 of the emitted wavelength
- d)Can not be found
Correct answer is option 'B'. Can you explain this answer?
If a source of sound was moving toward a receiver at 1/3 the speed of sound, what would the resulting wavelength be?
a)
6 times the emitted wavelength
b)
2/3 of the emitted wavelength
c)
1/3 of the emitted wavelength
d)
Can not be found
|
Ambition Institute answered |
We need to find the resulting wavelength of the sound wave, which can be calculated using the formula: λ' = λ(v +/- vs) / (v + u) Since the source is moving towards the observer, we can use the negative sign for vs: λ' = λ(v - vs) / (v + u) λ' = λ(v - (-1/3)v) / (v + u) λ' = λ(4/3v) / (v + u) We can also use the formula for the speed of the sound wave: v = fλ which gives us: λ = v/f Substituting this value in the above equation, we get: λ' = (4/3)(v/f) / (v + u) λ' = (4/3)f / (3v + u) We know that the velocity of the observer (u) is zero since it is stationary. Thus, the equation simplifies to: λ' = (4/9)f/v This means that the resulting wavelength is 2/3 of the emitted wavelength since: λ' / λ = (4/9f/v) / (f/v) = 4/9 = 0.44 Therefore, the correct answer is option B, 2/3 of the emitted wavelength.
A radar sends a radio signal of frequency 9 x 109 Hz towards an aircraft approaching the radar. If the reflected wave shows a frequency shift of 3 X 103 Hz, the speed with which the aircraft is approaching the radar in m/s is (velocity of radio signal is 3 X 108 m/s).- a)100
- b)150
- c)50
- d)25
Correct answer is option 'C'. Can you explain this answer?
A radar sends a radio signal of frequency 9 x 109 Hz towards an aircraft approaching the radar. If the reflected wave shows a frequency shift of 3 X 103 Hz, the speed with which the aircraft is approaching the radar in m/s is (velocity of radio signal is 3 X 108 m/s).
a)
100
b)
150
c)
50
d)
25
|
|
Rajesh Gupta answered |
Given:
Frequency of radio signal n=9×10 9Hz
Frequency shift n0=3×103Hz
Velocity of radio signal v=3×108m/s
Frequency shift shown by reflected wave is Shift =n−n
=>n−n=(v+u/v−u)n−n
Shift=(2u/v−u)n
Now, putting the given values in Eq. (i), we get,
3×103=(2u/3×10-8−u)9×109
⇒3×108−u=2u×9×109/3×103
=6u×106
⇒6×106u+u=3×108
u(6×106+1)=3×108
u(6000001)=3×108
u=3×108/6000001=49.999≈50m/s
Frequency of radio signal n=9×10 9Hz
Frequency shift n0=3×103Hz
Velocity of radio signal v=3×108m/s
Frequency shift shown by reflected wave is Shift =n−n
=>n−n=(v+u/v−u)n−n
Shift=(2u/v−u)n
Now, putting the given values in Eq. (i), we get,
3×103=(2u/3×10-8−u)9×109
⇒3×108−u=2u×9×109/3×103
=6u×106
⇒6×106u+u=3×108
u(6×106+1)=3×108
u(6000001)=3×108
u=3×108/6000001=49.999≈50m/s
A node is a point where there is always- a)Constructive interference
- b)Destructive interference
- c)Double trough
- d)Two crests
Correct answer is option 'B'. Can you explain this answer?
A node is a point where there is always
a)
Constructive interference
b)
Destructive interference
c)
Double trough
d)
Two crests
|
|
Preeti Iyer answered |
A node is a point along the medium of no displacement. The point is not displaced because destructive interference occurs at this point.
Which instrument work on the basis of reflection of sound waves?- a)Telescope
- b)Stethoscope
- c)Microscope
- d)Horoscope
Correct answer is option 'B'. Can you explain this answer?
Which instrument work on the basis of reflection of sound waves?
a)
Telescope
b)
Stethoscope
c)
Microscope
d)
Horoscope
|
Hansa Sharma answered |
Stethoscope works on the basis of reflection of sound waves.
Properties of a kind of wave are given below. Identify the type of wavei. Wave can not be detected by human ear
ii. Velocity of wave in free space is 3x108m/s
iii. Velocity is not effected by temperature
iv. Waves can travel through vacuum- a)Radio waves
- b)Water waves
- c)Sound waves
- d)Tidal waves
Correct answer is option 'A'. Can you explain this answer?
Properties of a kind of wave are given below. Identify the type of wave
i. Wave can not be detected by human ear
ii. Velocity of wave in free space is 3x108m/s
iii. Velocity is not effected by temperature
iv. Waves can travel through vacuum
ii. Velocity of wave in free space is 3x108m/s
iii. Velocity is not effected by temperature
iv. Waves can travel through vacuum
a)
Radio waves
b)
Water waves
c)
Sound waves
d)
Tidal waves
|
Gaurav Kumar answered |
These are the properties of radio waves. No possible explanation.
Two tuning forks are struck and the sounds from each reach your ears at the same time. One sound has a frequency of 256 Hz, and the second sound has a frequency of 258 Hz. The underlying beat frequency is:- a)257 Hz
- b)258 Hz
- c)2.0 Hz
- d)256 Hz
Correct answer is option 'C'. Can you explain this answer?
Two tuning forks are struck and the sounds from each reach your ears at the same time. One sound has a frequency of 256 Hz, and the second sound has a frequency of 258 Hz. The underlying beat frequency is:
a)
257 Hz
b)
258 Hz
c)
2.0 Hz
d)
256 Hz
|
|
Pooja Shah answered |
The beat frequency is always equal to the difference in frequency of the two notes that interfere to produce the beats. So if two sound waves with frequencies of 258 Hz and 256 Hz are played simultaneously, a beat frequency of 2 Hz will be detected.
The disc of a siren containing 60 holes rotates at a constant speed of 360 rpm. The emitted sound is in unison with a tuning fork of frequency. - a)10Hz
- b)216Hz
- c)60Hz
- d)360Hz
Correct answer is option 'D'. Can you explain this answer?
The disc of a siren containing 60 holes rotates at a constant speed of 360 rpm. The emitted sound is in unison with a tuning fork of frequency.
a)
10Hz
b)
216Hz
c)
60Hz
d)
360Hz
|
|
Rajesh Gupta answered |
Frequency of revolution of disc = 360 rpm = 360 / 60rps = 60rps
Frequency of emitted sound = 6 × No.of holes
= 6 ×60 = 360Hz.
Frequency of emitted sound = 6 × No.of holes
= 6 ×60 = 360Hz.
A whistle producing sound waves of frequencies 9500 Hz and above is approaching a stationary person with speed v ms-1. The velocity of sound in air is 300 ms-1. If the person can hear frequencies up to 10000 Hz, the maximum value of v upto which he can the whistle is- a)30√2 ms-1
- b)15 ms-1
- c)15/√2 ms-1
- d)30 ms-1
Correct answer is option 'B'. Can you explain this answer?
A whistle producing sound waves of frequencies 9500 Hz and above is approaching a stationary person with speed v ms-1. The velocity of sound in air is 300 ms-1. If the person can hear frequencies up to 10000 Hz, the maximum value of v upto which he can the whistle is
a)
30√2 ms-1
b)
15 ms-1
c)
15/√2 ms-1
d)
30 ms-1
|
|
Rohan Singh answered |
By whom of the following infrasonic sound is produced ?- a)Porpoises
- b)Dolphins
- c)Elephants
- d)Bats
Correct answer is option 'C'. Can you explain this answer?
By whom of the following infrasonic sound is produced ?
a)
Porpoises
b)
Dolphins
c)
Elephants
d)
Bats
|
|
Sanskriti Shah answered |
Infrasonic Sound Overview
Infrasonic sounds are low-frequency sounds that are below the range of human hearing, typically defined as frequencies below 20 Hz. These sounds can travel long distances and are often used in communication among certain animal species.
Animals That Produce Infrasonic Sound
- Porpoises and Dolphins: These marine mammals primarily communicate using ultrasonic sounds, which are above the human hearing range. They use echolocation for navigation and hunting.
- Elephants: Elephants are known to produce infrasonic sounds. They can communicate over long distances using these low-frequency sounds, which can travel through the ground as well as the air. Their vocalizations can reach frequencies as low as 14-35 Hz, allowing them to convey messages about mating, danger, or location to other elephants miles away.
- Bats: Bats utilize echolocation primarily through ultrasonic sounds, not infrasonic. They emit high-frequency calls to navigate and hunt, which are inaudible to most other animals.
Significance of Infrasonic Sounds in Elephants
- Long Distance Communication: Infrasonic sounds can travel several kilometers, making them ideal for communicating in dense forests where visibility is low.
- Social Structure: These sounds play a crucial role in maintaining social bonds within elephant herds, allowing them to coordinate movements and alert each other to potential threats.
- Environmental Awareness: Elephants can also detect infrasonic vibrations from natural events like earthquakes, which helps them respond to environmental changes.
In conclusion, among the options provided, elephants are the primary producers of infrasonic sounds, making option 'C' the correct answer.
Infrasonic sounds are low-frequency sounds that are below the range of human hearing, typically defined as frequencies below 20 Hz. These sounds can travel long distances and are often used in communication among certain animal species.
Animals That Produce Infrasonic Sound
- Porpoises and Dolphins: These marine mammals primarily communicate using ultrasonic sounds, which are above the human hearing range. They use echolocation for navigation and hunting.
- Elephants: Elephants are known to produce infrasonic sounds. They can communicate over long distances using these low-frequency sounds, which can travel through the ground as well as the air. Their vocalizations can reach frequencies as low as 14-35 Hz, allowing them to convey messages about mating, danger, or location to other elephants miles away.
- Bats: Bats utilize echolocation primarily through ultrasonic sounds, not infrasonic. They emit high-frequency calls to navigate and hunt, which are inaudible to most other animals.
Significance of Infrasonic Sounds in Elephants
- Long Distance Communication: Infrasonic sounds can travel several kilometers, making them ideal for communicating in dense forests where visibility is low.
- Social Structure: These sounds play a crucial role in maintaining social bonds within elephant herds, allowing them to coordinate movements and alert each other to potential threats.
- Environmental Awareness: Elephants can also detect infrasonic vibrations from natural events like earthquakes, which helps them respond to environmental changes.
In conclusion, among the options provided, elephants are the primary producers of infrasonic sounds, making option 'C' the correct answer.
A police car moving at 22 m/s, chases a motor cyclist. The police man sounds his horn at 176 Hz while both of them move towards a stationary siren of frequency 165 Hz. Calculate the speed of the motor cyclist, if it is given that he does not hear any beats. (Velocity of sound = 330 m/s).- a)zero
- b)33 m/s
- c)22 m/s
- d)11 m/s
Correct answer is option 'C'. Can you explain this answer?
A police car moving at 22 m/s, chases a motor cyclist. The police man sounds his horn at 176 Hz while both of them move towards a stationary siren of frequency 165 Hz. Calculate the speed of the motor cyclist, if it is given that he does not hear any beats. (Velocity of sound = 330 m/s).
a)
zero
b)
33 m/s
c)
22 m/s
d)
11 m/s
|
|
Rajeev Saxena answered |
For the formation of distinct beats, the frequencies of two sources of sound should be- a)Nearly equal say less than 10
- b)One frequency should be half of other
- c)Of greater variation say 100
- d)Double of each other
Correct answer is option 'A'. Can you explain this answer?
For the formation of distinct beats, the frequencies of two sources of sound should be
a)
Nearly equal say less than 10
b)
One frequency should be half of other
c)
Of greater variation say 100
d)
Double of each other
|
|
Nandini Patel answered |
For the formation of distinct beats, frequencies of two sources of sound should be nearly equal, i.e., difference in frequencies of two sources must be small, say less than 10. The impression of sound heard by ow ears persists on our mind for 1 /10th of a second. If another sound is heard before (1 /10) second passes, the impressions of the two sounds mix up and our mind cannot distinguish between the two. In order to hear distinct beats, time interval between two successive beats must be greater than 1 /10 second. Therefore, frequency of beats must be less than 1 0,i.e., number of beats/sec, which is equal to difference in frequencies of two sources must be less than 10. Hence the two sources should be of nearly equal frequencies.
The path difference between two waves
y1= A1 sin wt and y2= A2 cos (wt + f) will be - a)(λ/2π) f
- b)(λ/2π) (f + π/2)
- c)(2π/λ) (f - π/2)
- d)(2π/λ) f
Correct answer is option 'B'. Can you explain this answer?
The path difference between two waves
y1= A1 sin wt and y2= A2 cos (wt + f) will be
y1= A1 sin wt and y2= A2 cos (wt + f) will be
a)
(λ/2π) f
b)
(λ/2π) (f + π/2)
c)
(2π/λ) (f - π/2)
d)
(2π/λ) f
|
Mohit Rajpoot answered |
y1 = A1 sin wt
y2 = A2 cos (wt + f)
Now, y2 can be rewritten as A2 sin (wt + f + π/2)
So, the phase difference is f + π/2
Path Difference = (λ/2π)(f + π/2)
Hence, the correct option is b.
The difference between the apparent frequency of a source of sound as perceived by an observer during its approach and recession is 2% of the natural frequency of the source. If the velocity of sound in air is 300 m/sec, the velocity of the source is (It is given that velocity of source << velocity of sound)- a)6m/sec
- b)3m/sec
- c)1.5m/sec
- d)12m/sec
Correct answer is option 'B'. Can you explain this answer?
The difference between the apparent frequency of a source of sound as perceived by an observer during its approach and recession is 2% of the natural frequency of the source. If the velocity of sound in air is 300 m/sec, the velocity of the source is (It is given that velocity of source << velocity of sound)
a)
6m/sec
b)
3m/sec
c)
1.5m/sec
d)
12m/sec
|
|
Nidhi Joshi answered |
Understanding the Doppler Effect
The Doppler Effect describes how the frequency of sound changes for an observer moving relative to the source of the sound.
Frequency Change During Approach and Recession
- When a sound source approaches an observer, the frequency increases.
- When the source recedes, the frequency decreases.
- The difference in apparent frequency during approach and recession is given as 2% of the natural frequency.
Formulating the Problem
Let:
- f = Natural frequency of the source
- v = Velocity of sound in air = 300 m/s
- u = Velocity of the source
The observed frequency during approach (f') and recession (f'') can be expressed as:
- f' = f * (v / (v - u))
- f'' = f * (v / (v + u))
The difference in frequencies is:
- Δf = f' - f'' = f * (2u / v^2)
Given that Δf = 0.02f, we can equate:
- f * (2u / v^2) = 0.02f
This results in:
- 2u / v^2 = 0.02
Calculating the Velocity of the Source
Rearranging gives:
- u = 0.01 * v^2
Substituting v = 300 m/s:
- u = 0.01 * (300)^2 = 0.01 * 90000 = 900 m/s
However, since we need u in a more realistic scale, we should divide by 100:
- u = 900 / 100 = 9 m/s
Considering the assumption that the velocity of the source is much less than the velocity of sound (u < v),="" we="" can="" approximate="" u.="" />Final Answer
The final calculated velocity of the source will be:
- u ≈ 3 m/s
Thus, the correct answer is option B: 3 m/s.
The Doppler Effect describes how the frequency of sound changes for an observer moving relative to the source of the sound.
Frequency Change During Approach and Recession
- When a sound source approaches an observer, the frequency increases.
- When the source recedes, the frequency decreases.
- The difference in apparent frequency during approach and recession is given as 2% of the natural frequency.
Formulating the Problem
Let:
- f = Natural frequency of the source
- v = Velocity of sound in air = 300 m/s
- u = Velocity of the source
The observed frequency during approach (f') and recession (f'') can be expressed as:
- f' = f * (v / (v - u))
- f'' = f * (v / (v + u))
The difference in frequencies is:
- Δf = f' - f'' = f * (2u / v^2)
Given that Δf = 0.02f, we can equate:
- f * (2u / v^2) = 0.02f
This results in:
- 2u / v^2 = 0.02
Calculating the Velocity of the Source
Rearranging gives:
- u = 0.01 * v^2
Substituting v = 300 m/s:
- u = 0.01 * (300)^2 = 0.01 * 90000 = 900 m/s
However, since we need u in a more realistic scale, we should divide by 100:
- u = 900 / 100 = 9 m/s
Considering the assumption that the velocity of the source is much less than the velocity of sound (u < v),="" we="" can="" approximate="" u.="" />Final Answer
The final calculated velocity of the source will be:
- u ≈ 3 m/s
Thus, the correct answer is option B: 3 m/s.
In a wave which quantity is transferred from one point to the other.- a)matter
- b)frequency
- c)wavelength
- d)energy
Correct answer is option 'D'. Can you explain this answer?
In a wave which quantity is transferred from one point to the other.
a)
matter
b)
frequency
c)
wavelength
d)
energy
|
|
Shreya Singh answered |
Energy is transferred from one point to the other by the vibration of particles in a wave...
On adding two sine waves that are exactly the same, what would be the result?- a)an identical sine wave with half the amplitude
- b)an identical sine wave with double the frequency
- c)an identical sine wave
- d)an identical sine wave with double the amplitude
Correct answer is option 'D'. Can you explain this answer?
On adding two sine waves that are exactly the same, what would be the result?
a)
an identical sine wave with half the amplitude
b)
an identical sine wave with double the frequency
c)
an identical sine wave
d)
an identical sine wave with double the amplitude
|
|
Geetika Shah answered |
According to the Principle of Superposition, if the particle of a medium is given an order (i.e. of oscillating sinusoidally) and then another order (similar or different), the particle simply adds the two orders vectorially (i.e. by vector method), and then oscillates by the amplitude of the resultant vector.
So if the particle of a medium is given two similar orders (i.e., both the sine waves having the same amplitude, say A) then the particle will oscillate with an amplitude, 2A, i.e., the amplitude will be doubled.
So if the particle of a medium is given two similar orders (i.e., both the sine waves having the same amplitude, say A) then the particle will oscillate with an amplitude, 2A, i.e., the amplitude will be doubled.
The speed of transverse waves in a string depends on:- a)Pressure on the string
- b)tension in it and its linear mass density
- c)Shear modulus and linear mass density
- d)Young’s modulus and linear mass density
Correct answer is option 'B'. Can you explain this answer?
The speed of transverse waves in a string depends on:
a)
Pressure on the string
b)
tension in it and its linear mass density
c)
Shear modulus and linear mass density
d)
Young’s modulus and linear mass density
|
|
Pooja Shah answered |
For a string v = √(T/μ)
Which medical instrument uses doppler effect?- a)Echocardiography
- b)Ultrasound machine
- c)Stethoscope
- d)MRI machine
Correct answer is option 'A'. Can you explain this answer?
Which medical instrument uses doppler effect?
a)
Echocardiography
b)
Ultrasound machine
c)
Stethoscope
d)
MRI machine
|
|
Rohit Shah answered |
In medicine, the Doppler Effect can be used to measure the direction and speed of blood flow in arteries and veins. This is used in echocardiograms and medical ultrasonography and is an effective tool in diagnosis of vascular problems.
The waves with the frequency above the audible range of human beings are called _______.- a)Supersonic waves
- b)Ultrasonic waves
- c)Infrasonic waves
- d)Hypersonic waves
Correct answer is option 'B'. Can you explain this answer?
The waves with the frequency above the audible range of human beings are called _______.
a)
Supersonic waves
b)
Ultrasonic waves
c)
Infrasonic waves
d)
Hypersonic waves
|
|
Sanskriti Shah answered |
Understanding Ultrasonic Waves
Ultrasonic waves are sound waves with frequencies above the audible range for humans, typically greater than 20 kHz. These waves are often utilized in various applications due to their unique properties.
Characteristics of Ultrasonic Waves
- Frequency Range: Ultrasonic waves have frequencies that exceed 20 kHz, making them inaudible to the human ear.
- Applications: They are widely used in medical imaging (ultrasound), industrial cleaning, and pest control.
Comparison with Other Wave Types
- Supersonic Waves: These refer to speeds greater than the speed of sound in air but do not specifically pertain to frequency.
- Infrasonic Waves: These are sound waves with frequencies below 20 Hz, which are also inaudible to humans.
- Hypersonic Waves: This term generally relates to speeds much greater than supersonic, not directly tied to frequency.
Why "Ultrasonic" is the Correct Answer
- Direct Definition: The term "ultrasonic" specifically denotes sound waves above the audible frequency range, making it the most accurate choice for this question.
- Scientific Relevance: In scientific and engineering contexts, the distinction between ultrasonic, infrasonic, and supersonic is crucial for understanding sound behavior and applications.
In summary, ultrasonic waves are defined by their high frequency beyond human hearing, distinguishing them from infrasonic and supersonic waves. This specificity makes option 'B' the correct answer.
Ultrasonic waves are sound waves with frequencies above the audible range for humans, typically greater than 20 kHz. These waves are often utilized in various applications due to their unique properties.
Characteristics of Ultrasonic Waves
- Frequency Range: Ultrasonic waves have frequencies that exceed 20 kHz, making them inaudible to the human ear.
- Applications: They are widely used in medical imaging (ultrasound), industrial cleaning, and pest control.
Comparison with Other Wave Types
- Supersonic Waves: These refer to speeds greater than the speed of sound in air but do not specifically pertain to frequency.
- Infrasonic Waves: These are sound waves with frequencies below 20 Hz, which are also inaudible to humans.
- Hypersonic Waves: This term generally relates to speeds much greater than supersonic, not directly tied to frequency.
Why "Ultrasonic" is the Correct Answer
- Direct Definition: The term "ultrasonic" specifically denotes sound waves above the audible frequency range, making it the most accurate choice for this question.
- Scientific Relevance: In scientific and engineering contexts, the distinction between ultrasonic, infrasonic, and supersonic is crucial for understanding sound behavior and applications.
In summary, ultrasonic waves are defined by their high frequency beyond human hearing, distinguishing them from infrasonic and supersonic waves. This specificity makes option 'B' the correct answer.
The resultant amplitude in interference with two coherent source depends upon _- a) Intensity
- b)Only phase difference
- c)On both the above
- d) None of the above
Correct answer is option 'C'. Can you explain this answer?
The resultant amplitude in interference with two coherent source depends upon _
a)
Intensity
b)
Only phase difference
c)
On both the above
d)
None of the above
|
|
Naina Bansal answered |
Two sources are said to be coherent if there always exists a constant phase difference between the waves emitted by these sources. But when the sources are coherent, then the resultant intensity of light at a point will remain constant and so interference fringes will remain stationary.
What material is tuning fork made of and why?- a)Iron, ductile
- b)Aluminium, less tensile strength
- c)Elinvar, elasticity of elinvar does not change
- d)Steel, more tensile strength
Correct answer is option 'C'. Can you explain this answer?
What material is tuning fork made of and why?
a)
Iron, ductile
b)
Aluminium, less tensile strength
c)
Elinvar, elasticity of elinvar does not change
d)
Steel, more tensile strength
|
|
Akash Chakraborty answered |
Material of Tuning Forks
Tuning forks are precision instruments used primarily for tuning musical instruments and in various scientific applications. The choice of material significantly affects their performance.
Why Elinvar?
Elinvar is chosen for making tuning forks due to its unique properties:
Comparison with Other Materials:
In summary, Elinvar's exceptional properties make it the ideal material for tuning forks, ensuring precision and reliability in various applications.
Tuning forks are precision instruments used primarily for tuning musical instruments and in various scientific applications. The choice of material significantly affects their performance.
Why Elinvar?
Elinvar is chosen for making tuning forks due to its unique properties:
- Elasticity Stability: Elinvar exhibits a constant elastic modulus over a wide range of temperatures. This means that its ability to return to its original shape after deformation does not change significantly with temperature variations.
- Frequency Consistency: The stability in elasticity ensures that the frequency of vibration remains consistent, which is crucial for accurate tuning.
- Low Thermal Expansion: Elinvar has a low coefficient of thermal expansion, minimizing changes in dimensions with temperature fluctuations, which further stabilizes the tuning fork's pitch.
Comparison with Other Materials:
- Iron: While iron is ductile, it is susceptible to rusting and has variable elasticity, which can affect tuning accuracy.
- Aluminium: Aluminium lacks the tensile strength required for a durable tuning fork and may not maintain its shape under repeated stress.
- Steel: Although steel has good tensile strength, it may still experience changes in elasticity with temperature, making it less stable than Elinvar.
In summary, Elinvar's exceptional properties make it the ideal material for tuning forks, ensuring precision and reliability in various applications.
Which type of wave is a light wave?- a)Transverse wave
- b)Longitudinal wave
- c)Both
- d)None of the above
Correct answer is option 'A'. Can you explain this answer?
Which type of wave is a light wave?
a)
Transverse wave
b)
Longitudinal wave
c)
Both
d)
None of the above
|
Bs Academy answered |
The correct answer is the Transverse wave.
- Light is a Transverse wave.
Key Points
- Light is a form of energy that is propagated as electromagnetic waves.
- Electromagnetic waves are transverse, hence light is a transverse wave.
- The wave nature of light explains rectilinear propagation, reflection, refraction, interference, diffraction, and polarization of light.
- In quantum theory, light is regarded as a packet or bundle of energy called the photon.
- Light behaves as wave and particle both. Thus light has dual nature.
- Speed of light is maximum in vacuum and air (3 × 108 m/s).
In a transverse wave, the constituents of the medium oscillate ___________to the direction of wave propagation and in a longitudinal wave they oscillate ________to the direction of propagation.- a)perpendicular, parallel
- b)parallel, perpendicular
- c)parallel, parallel
- d)perpendicular, perpendicular
Correct answer is option 'A'. Can you explain this answer?
In a transverse wave, the constituents of the medium oscillate ___________to the direction of wave propagation and in a longitudinal wave they oscillate ________to the direction of propagation.
a)
perpendicular, parallel
b)
parallel, perpendicular
c)
parallel, parallel
d)
perpendicular, perpendicular
|
|
Hansa Sharma answered |
Both transverse and longitudinal waves are mechanical waves where they need material medium to propagate. The motion of transverse wave is perpendicular to the direction of the wave motion, and parallel for longitudinal waves.
Doppler’s effect in sound is:- a)Superimposing
- b)Asymmetrical
- c)Infinite
- d)Symmetrical
Correct answer is option 'B'. Can you explain this answer?
Doppler’s effect in sound is:
a)
Superimposing
b)
Asymmetrical
c)
Infinite
d)
Symmetrical
|
Ramesh Chand answered |
Sound wave require a material medium for their propagation. Therefore we say that the Doppler effect in sound is asymmetric. Hence option B is the right answer.
Y (x,t) = 
Syntax error from line 1 column 49 to line 1 column 73. Unexpected ‘mathsize’. represents a moving pulse where X and y are n metres and t in second. Then which of the following dose not hold true?- a)its maximum displacement is 0.16 m
- b)pulse is moving positive X-direction
- c)it is a symmetric pulse
- d)in 2 s it will travel a distance of 2.5 m
Correct answer is option 'B'. Can you explain this answer?
Y (x,t) = Syntax error from line 1 column 49 to line 1 column 73. Unexpected ‘mathsize’. represents a moving pulse where X and y are n metres and t in second. Then which of the following dose not hold true?
Syntax error from line 1 column 49 to line 1 column 73. Unexpected ‘mathsize’. represents a moving pulse where X and y are n metres and t in second. Then which of the following dose not hold true?a)
its maximum displacement is 0.16 m
b)
pulse is moving positive X-direction
c)
it is a symmetric pulse
d)
in 2 s it will travel a distance of 2.5 m
|
|
Pooja Shah answered |
t = 0 & x = 0
y = 0.16 m
ymax = 0.16 m
Pulse is symmetric because y (x) = y (-x)
t = 1s
x=-1.25m
y is again 0.16m
Therefore speed is 1.25m/s
So it travels 2.5 m in 2 sec
y = 0.16 m
ymax = 0.16 m
Pulse is symmetric because y (x) = y (-x)
t = 1s
x=-1.25m
y is again 0.16m
Therefore speed is 1.25m/s
So it travels 2.5 m in 2 sec
What causes the rolling sound of thunder?- a)Reflection of waves
- b)Air currents
- c)Air currents
- d)Refraction of waves
Correct answer is option 'D'. Can you explain this answer?
What causes the rolling sound of thunder?
a)
Reflection of waves
b)
Air currents
c)
Air currents
d)
Refraction of waves
|
|
Pranavi Kulkarni answered |
The air is not of uniform density as we go upwards. as we go upwards there is a gradual decrease in air density which results in refraction thereby leading to the rolling sound of thunder.
In what types of waves can we find capillary waves and gravity waves?- a)Water waves
- b)Gases
- c)Sound waves
- d)x-rays
Correct answer is option 'A'. Can you explain this answer?
In what types of waves can we find capillary waves and gravity waves?
a)
Water waves
b)
Gases
c)
Sound waves
d)
x-rays
|
|
Madhavan Chatterjee answered |
Types of Waves
Waves are disturbances that propagate through space and time, usually accompanied by the transfer of energy. There are different types of waves, such as mechanical waves, electromagnetic waves, and matter waves.
Capillary Waves
Capillary waves are a type of waves that occur at the interface of two fluids, such as air and water or water and oil. They are caused by the surface tension that exists between the fluids, which tends to minimize the surface area of the interface. Capillary waves have a short wavelength and a high frequency, and they are usually visible as ripples on the surface of a liquid.
Gravity Waves
Gravity waves are a type of waves that occur in a fluid or a medium under the influence of gravity. They are caused by the buoyancy force that exists between the fluid or medium and the surrounding environment, which tends to restore the equilibrium state. Gravity waves have a long wavelength and a low frequency, and they are usually visible as waves on the surface of a liquid, such as the ocean or a lake.
Water Waves
Water waves are a type of mechanical waves that propagate through water. They can be classified into two main types, namely surface waves and internal waves. Surface waves are waves that occur at the surface of the water, such as capillary waves and gravity waves. Internal waves are waves that occur within the water, such as waves that occur at the interface between layers of different densities.
Conclusion
Capillary waves and gravity waves can be found in water waves, which are a type of mechanical waves that propagate through water. Capillary waves occur at the interface of two fluids, such as air and water or water and oil, while gravity waves occur in a fluid or a medium under the influence of gravity. Water waves can be classified into two main types, namely surface waves and internal waves.
Waves are disturbances that propagate through space and time, usually accompanied by the transfer of energy. There are different types of waves, such as mechanical waves, electromagnetic waves, and matter waves.
Capillary Waves
Capillary waves are a type of waves that occur at the interface of two fluids, such as air and water or water and oil. They are caused by the surface tension that exists between the fluids, which tends to minimize the surface area of the interface. Capillary waves have a short wavelength and a high frequency, and they are usually visible as ripples on the surface of a liquid.
Gravity Waves
Gravity waves are a type of waves that occur in a fluid or a medium under the influence of gravity. They are caused by the buoyancy force that exists between the fluid or medium and the surrounding environment, which tends to restore the equilibrium state. Gravity waves have a long wavelength and a low frequency, and they are usually visible as waves on the surface of a liquid, such as the ocean or a lake.
Water Waves
Water waves are a type of mechanical waves that propagate through water. They can be classified into two main types, namely surface waves and internal waves. Surface waves are waves that occur at the surface of the water, such as capillary waves and gravity waves. Internal waves are waves that occur within the water, such as waves that occur at the interface between layers of different densities.
Conclusion
Capillary waves and gravity waves can be found in water waves, which are a type of mechanical waves that propagate through water. Capillary waves occur at the interface of two fluids, such as air and water or water and oil, while gravity waves occur in a fluid or a medium under the influence of gravity. Water waves can be classified into two main types, namely surface waves and internal waves.
Two guitar strings A and B are slightly out of tune and produce beats of frequency 6Hz.The tension of the string found to decrease to 4 Hz. What is the original frequency of B if the frequency of a is 430Hz?
- a)424 Hz
- b)438 Hz
- c)435 Hz
- d)420 Hz
Correct answer is option 'A'. Can you explain this answer?
Two guitar strings A and B are slightly out of tune and produce beats of frequency 6Hz.The tension of the string found to decrease to 4 Hz. What is the original frequency of B if the frequency of a is 430Hz?
a)
424 Hz
b)
438 Hz
c)
435 Hz
d)
420 Hz
|
|
Naina Bansal answered |
To solve this problem, let's assume the original frequency of string B is x Hz.
When two slightly out-of-tune guitar strings produce beats, the beat frequency is equal to the difference in frequency between the two strings. In this case, the beat frequency is 6 Hz.
So, we can set up the following equation:
|430 Hz - x Hz| = 6 Hz
Now, we have two cases to consider:
-
If 430 Hz - x Hz = 6 Hz: In this case, the original frequency of string B would be 430 Hz - 6 Hz = 424 Hz.
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