Tag: time period, frequency and amplitude of sound

Questions Related to time period, frequency and amplitude of sound

State whether true or false.
The needle of a moving sewing machine executes oscillatory motion.

physics sound: production of sound oscillation - amplitude, time period and frequency of oscillation time period, frequency and amplitude of sound oscillatory and periodic motion

  1. True

  2. False

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Correct Option: A
Explanation:

The needle of swing machine has a to and fro motion about mea position. So, its a oscillatory motion.

Simple harmonic oscillation of a given system can be specified completely by stating its: 

physics sound: production of sound oscillation - amplitude, time period and frequency of oscillation time period, frequency and amplitude of sound oscillatory and periodic motion

  1. amplitude, frequency and initial phase.

  2. amplitude, frequency and wavelength

  3. frequency and wavelength.

  4. frequency, wavelength and initial phase.

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Correct Option: A
Explanation:

Although waves consist of oscillation, there is no wavelength in a pure oscillation. It is there only in waves. 

Simple harmonic motion (SHM) is a technical term used to describe a certain kind of idealized oscillation. Practically all the oscillations that one can see directly in the natural world are much more complicated than SHM. Why then do physicists make such a big deal out of studying SHM?

physics sound: production of sound oscillation - amplitude, time period and frequency of oscillation time period, frequency and amplitude of sound oscillatory and periodic motion

  1. It is the only kind of oscillation that can be described mathematically

  2. Any real oscillation can be analysed as a superposition (sum or integral) of SHMs with different frequencies

  3. Physics is concerned mainly with the unnatural world.

  4. Students are too stupid to appreciate the real world.

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Correct Option: B
Explanation:

Simple harmonic motion provides a basis for the characterization of more complicated motions through the techniques of Fourier analysis. Here any waveform can be represented as closely as desired by the combination of a sufficiently large number of sinusoidal waves that form a harmonic series.   Fourier's theorem suggests that any periodic function can be represented as an algebraic sum of sine and cosine functions called a Fourier Series. 

Which of the following conditions must be satisfied for a body to oscillate or vibrate?
A: The body must have inertia to keep it moving across the mid point of its path.
B: There must be a restoring force to accelerate the body towards the midpoint.
C: The fractional force acting on the body against its motion must be small.

physics sound: production of sound oscillation - amplitude, time period and frequency of oscillation time period, frequency and amplitude of sound oscillatory and periodic motion

  1. Only A

  2. Only A and B

  3. Only B and C

  4. All A, B and C

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Correct Option: D

An object swinging on the end of a string forms a simple pendulum. Some students (and some texts) often cite the simple pendulum's motion as an example of SHM. That is not quite accurate because the motion is really

physics sound: production of sound oscillation - amplitude, time period and frequency of oscillation time period, frequency and amplitude of sound oscillatory and periodic motion

  1. approximately SHM only for small amplitudes

  2. exactly SHM only for amplitudes that are smaller than a certain value

  3. approximately SHM for all amplitudes.

  4. None of the above

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Correct Option: A
Explanation:

An object performing SHM moves along a straight path.

For large amplitudes, a pendulum moves in a curved path.

Which of  the  following regarding oscillatory motion is true?

physics sound: production of sound oscillation - amplitude, time period and frequency of oscillation time period, frequency and amplitude of sound oscillatory and periodic motion

  1. Motion of the earth is periodic but not oscillatory because it is not to and fro.

  2. Quivering of the string of the musical instrument is an example of oscillatory motion

  3. Motion of the earth is periodic and oscillatory motion because it is not to and fro.

  4. None of the above

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Correct Option: A
Explanation:

Oscillator motion is to and fro motion about a mean position. Earth motion is not a to and fro motion here, hence it is not an oscillatory motion. But as earth motion is repeated in a regular interval of time, its motion is periodic.

Which of the following is an example of oscillatory motion? 

physics sound: production of sound oscillation - amplitude, time period and frequency of oscillation time period, frequency and amplitude of sound oscillatory and periodic motion

  1. Heart beat of a persion

  2. Motion of earth around the sun

  3. Motion of Hally's comet around the sun

  4. Oscillations of a simple pendulam

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Correct Option: D
Explanation:

Oscillation of a simple pendulum is a simple harmonic motion.

The displacement of a particle is represented by the equation $y=sin^3(\omega t)$. The motion is 

physics sound: production of sound oscillation - amplitude, time period and frequency of oscillation time period, frequency and amplitude of sound oscillatory and periodic motion

  1. non-periodic

  2. periodic but not simple harmonic

  3. simple harmonic with period $\dfrac{2 \pi}{\omega}$

  4. simple harmonic with period $\dfrac{\pi}{\omega}$

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Correct Option: B
Explanation:

Given the equation of displacement of the particle, $y={ sin }^{ 3 }\omega t$

We know $sin3\theta =3sin\theta -4{ sin }^{ 3 }\theta $
Hence, $y=\frac { (3sin\omega t-4sin3\omega t) }{ 4 } \ \Rightarrow 4\frac { dy }{ dt } =3\omega cos\omega t-4\times [3\omega cos3\omega t]\ \Rightarrow 4\times \frac { { d }^{ 2 }y }{ { dt }^{ 2 } } =-3{ \omega  }^{ 2 }sin\omega t+12\omega sin3\omega t\ \Rightarrow \frac { { d }^{ 2 }y }{ { dt }^{ 2 } } =\frac { -3{ \omega  }^{ 2 }sin\omega t+12\omega sin3\omega t }{ 4 } \ \Rightarrow \frac { { d }^{ 2 }y }{ { dt }^{ 2 } } $ is not proportional to y. 
Hence, the motion is not SHM. 
As the expression is involving sine function, hence it will be periodic. 
Also ${ sin }^{ 3 }\omega t={ \left( sin\omega t \right)  }^{ 3 }\ ={ [sin(\omega t+2\pi )] }^{ 3 }\ ={ [sin(\omega t+2\pi /\omega )] }^{ 3 }$
Hence, $y={ sin }^{ 3 }\omega t$ represents a periodic motion with period $2\pi /\omega $.

A horizontal plank has a rectangular block placed on it. The plank starts oscillating vertically and simple harmonically with an amplitude of 40 cm. The block just loses contact with the plank when the later is momentarily at rest. Then

physics sound: production of sound oscillation - amplitude, time period and frequency of oscillation time period, frequency and amplitude of sound oscillatory and periodic motion

  1. the period of oscillation is $2\pi /5\ s$

  2. the block weighs double its weight when the plank is at one of the positions of momentary at rest

  3. the block weighs 1.5 times its weight on the plank half way down

  4. the block weighs its true weight on the plank, when the latter moves fast

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Correct Option: B

In an electronic watch, the component corresponding to the pendulum of a pendulum clock is a__?

physics sound: production of sound oscillation - amplitude, time period and frequency of oscillation time period, frequency and amplitude of sound oscillatory and periodic motion

  1. Diode

  2. Transistor

  3. Crystal oscillator

  4. Balance wheel

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Correct Option: C