PHYSICS NOTES 10TH CLASS
Written by BILAL HASAN B.cs , M.cs..
NICE STUDIES ACADEMY
WAVES AND MOTION
WAVES AND MOTION
BILAL HASAN:BORROWED FEATHERS SELDOM FIT.
WWW.URDULECTURESOFSCIENCE.BLOGSPOT.COM
DEFINITIONS
1. Vibration
One complete round trip of a simple harmonic motion is called vibration.
or
If a body in periodic motion moves to and fro over the same path, this motion is called Oscillation.
2. Time Period (T)
The time required to complete vibration is known as time period.
3. Frequency
It is the number of vibrations executed by an oscillating body in one second.
4. Displacement
It is the distance of a vibrating body at any instant from the equilibrium position.
5. Amplitude
The maximum distance of the body on either side of its equilibrium position is known as amplitude.
6. Wave Length
The distance between two consecutive crests and troughs is called wavelength.
10. Octave
The interval between a waveform and another of twice the frequency is known as Octave.
Units
Frequency: Cycles per second (eps) or Hertz (hz)
Wavelength: Meter
Intensity of Sound: Watt/meter2 or W/m2
Noise: Decibel (DB)
Simple Harmonic Motion (S.H.M)
Definition
"To and fro motion of a body in which acceleration is directly proportional to displacement and always directed towards mean position is known as Simple Harmonic Motion."
Condition for S.H.M
The conditions for simple Harmonic Motion are given below:
Some resisting force must act upon the body.
Acceleration must be directly proportional to the displacement.
Acceleration should be directed towards mean position.
System should be elastic.
Examples
Following are the examples of S.H.M:
Body attached to a spring horizontally on an ideal smooth surface.
Motion of a simple and compound pendulum.
Motion of a swing.
Motion of the projection of a body in a circle with uniform circular motion.
Resonance
Definition
"The large amplitude vibration of an object when given impulses at its natural frequency is known as Resonance."
Experiment
Consider a long string stretched tightly between two pegs. Four pendulums A, B, C and D of different lengths are fastened to the string. Another pendulum E of same length as A is also fastened.
When pendulum E is set to vibrate, it will be observed that all the pendulums start to swing but pendulum A begins to vibrate with larger amplitude, as pendulum E is set into vibration. It imparts its motion to the string. This string in turn imparts the same periodic motion to the pendulums. The natural frequency of all other pendulums except A is different. Due to the same natural frequency only A vibrates as the same vibration of E. This phenomenon under which pendulum A begin to vibrate is called resonance.
Example
March of Soldiers while Crossing the Bridge
Each bridge has its own natural frequency and marching of soldiers is another vibrating system. So there may occur a force on vibration in bridge. This may damage the bridge. So, for safely precautions, it is written that soldiers must march out of stop while crossing the bridge.
1. Vibration
One complete round trip of a simple harmonic motion is called vibration.
or
If a body in periodic motion moves to and fro over the same path, this motion is called Oscillation.
2. Time Period (T)
The time required to complete vibration is known as time period.
3. Frequency
It is the number of vibrations executed by an oscillating body in one second.
4. Displacement
It is the distance of a vibrating body at any instant from the equilibrium position.
5. Amplitude
The maximum distance of the body on either side of its equilibrium position is known as amplitude.
6. Wave Length
The distance between two consecutive crests and troughs is called wavelength.
10. Octave
The interval between a waveform and another of twice the frequency is known as Octave.
Units
Frequency: Cycles per second (eps) or Hertz (hz)
Wavelength: Meter
Intensity of Sound: Watt/meter2 or W/m2
Noise: Decibel (DB)
Simple Harmonic Motion (S.H.M)
Definition
"To and fro motion of a body in which acceleration is directly proportional to displacement and always directed towards mean position is known as Simple Harmonic Motion."
Condition for S.H.M
The conditions for simple Harmonic Motion are given below:
Some resisting force must act upon the body.
Acceleration must be directly proportional to the displacement.
Acceleration should be directed towards mean position.
System should be elastic.
Examples
Following are the examples of S.H.M:
Body attached to a spring horizontally on an ideal smooth surface.
Motion of a simple and compound pendulum.
Motion of a swing.
Motion of the projection of a body in a circle with uniform circular motion.
Resonance
Definition
"The large amplitude vibration of an object when given impulses at its natural frequency is known as Resonance."
Experiment
Consider a long string stretched tightly between two pegs. Four pendulums A, B, C and D of different lengths are fastened to the string. Another pendulum E of same length as A is also fastened.
When pendulum E is set to vibrate, it will be observed that all the pendulums start to swing but pendulum A begins to vibrate with larger amplitude, as pendulum E is set into vibration. It imparts its motion to the string. This string in turn imparts the same periodic motion to the pendulums. The natural frequency of all other pendulums except A is different. Due to the same natural frequency only A vibrates as the same vibration of E. This phenomenon under which pendulum A begin to vibrate is called resonance.
Example
March of Soldiers while Crossing the Bridge
Each bridge has its own natural frequency and marching of soldiers is another vibrating system. So there may occur a force on vibration in bridge. This may damage the bridge. So, for safely precautions, it is written that soldiers must march out of stop while crossing the bridge.
Wave
Definition
" A method of energy transfer involving some form of vibration is known as a wave."
Wave Motion
Wave motion is a form of disturbance, which travels through a medium due to periodic motion of particles of the medium about their mean position.
Experiment
We see that if we dip a pencil into a tap of water and take it out a pronounced circular ripple is set up on the water surface and travels towards the edges of the tub. However if we dip the pencil and take it out many times, a number of ripples will be formed one after the other.
Waves can also be produced on very long ropes. If one end of the rope is fixed and the other end is given sudden up and down jerk, a pulse-shaped wave is formed which travels along the rope.
Transverse Wave
Definition
"The wave in which amplitude is perpendicular to the direction of wave motion is known as Transverse Wave."
Examples
Radio Waves
Light Waves
Micro Waves
Waves in Water
Waves in String
Longitudinal Wave OR COMPRESSIONAL WAVES
Definition
"The wave in which amplitude is parallel to wave motion is called longitudinal wave."
Example
Sound Waves
Seismic Waves
Definition
" A method of energy transfer involving some form of vibration is known as a wave."
Wave Motion
Wave motion is a form of disturbance, which travels through a medium due to periodic motion of particles of the medium about their mean position.
Experiment
We see that if we dip a pencil into a tap of water and take it out a pronounced circular ripple is set up on the water surface and travels towards the edges of the tub. However if we dip the pencil and take it out many times, a number of ripples will be formed one after the other.
Waves can also be produced on very long ropes. If one end of the rope is fixed and the other end is given sudden up and down jerk, a pulse-shaped wave is formed which travels along the rope.
Transverse Wave
Definition
"The wave in which amplitude is perpendicular to the direction of wave motion is known as Transverse Wave."
Examples
Radio Waves
Light Waves
Micro Waves
Waves in Water
Waves in String
Longitudinal Wave OR COMPRESSIONAL WAVES
Definition
"The wave in which amplitude is parallel to wave motion is called longitudinal wave."
Example
Sound Waves
Seismic Waves
Difference Between Longitudinal and Transverse Waves
Longitudinal Waves
1. In longitudinal waves, particles of the medium vibrate in the direction of the waves.
2. The portion of wave in which particles of medium are very close to each other is called compression.
3. Examples of longitudinal waves are sound wave and seismic waves.
4. Distance between the centre of two compressions and rarefactions is called wavelength.
Transverse Waves
1. In transverse waves, particles of the medium vibrate in the direction perpendicular to the direction of wave.
2. The portion in which particles of medium are higher than their normal position is called crest.
3. Examples of transverse wave are microwaves and radio waves.
4. Distance between two crests and troughs is called wavelength.
Longitudinal Waves
1. In longitudinal waves, particles of the medium vibrate in the direction of the waves.
2. The portion of wave in which particles of medium are very close to each other is called compression.
3. Examples of longitudinal waves are sound wave and seismic waves.
4. Distance between the centre of two compressions and rarefactions is called wavelength.
Transverse Waves
1. In transverse waves, particles of the medium vibrate in the direction perpendicular to the direction of wave.
2. The portion in which particles of medium are higher than their normal position is called crest.
3. Examples of transverse wave are microwaves and radio waves.
4. Distance between two crests and troughs is called wavelength.
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