Programmed Learning Material

Name:Divya JaiswalID NO.:14162083Method: ScienceB.Ed Programme

Navrachna University

Instructional Objective

The students will be able to define wave,motion and Sound.

Students will be able to identify units of all the three Quantity.

Students will be able to distinguish between wave and motion.

Students will be able to calculate wavelength of sound.

Students will be able to explain the structure of internal ear.

Students will be able to define intensity and loudness of sound.

Students will be able to describe the characteristic of wave.

Students will be able to differentiate 3 types of sound.

Content Instruction

Students have to follow the given task and after that they have to test their progress just given after every task.And check their progress also by clicking the option given in each answer.

and any answer goes wrong then repeat the task again.And solve questions again.

Lets read about wave,motion and

sound

WAVE MOTIONS AND

SOUND

Vibrations are common in many elastic materials, and you can see and hear the results of many in your surroundings. Other vibrations in your surroundings, such as those involved in heat, electricity, and light, are invisible to the senses.

Forces and Elastic Materials.

Forces and Vibrations:A vibration is a repeating motion that moves back and

forth.

A mass on a frictionless surface is at rest at an equilibrium position (A) when undisturbed. When the spring is stretched (B) or compressed (D), then released (C), the mass vibrates back and forth because restoring forces pull opposite to and proportional to the displacement.

Describing Vibrations.A vibrating mass is described by measuring several

variables.The extent of displacement from the equilibrium

position.A cycle is the movement from some point, to

another point and back again.A period (T) is the time required for one

complete cycle.Frequency (f) is the number of cycles per

second.• Frequency is measured in Hertz (Hz)• The period is the time for one cycle and the

frequency is the cycles per second, the relationship is: T=1/f F = 1/T

A vibrating mass attached to a spring is displaced from rest, or equilibrium, position, and then released. The maximum displacement is called the amplitude of the vibration. A cycle is one complete vibration. The period is the time required for one complete cycle. The frequency is a count of how many cycles it completes in 1s.

A graph of simple harmonic motion is described by a sinusoidal curve.

Waves.

Kinds of Waves.Longitudinal Wave

A wave that travels in a back and forth movement

Transverse WaveA wave that disturbs particles in a perpendicular motion in

the direction of the wave.

(A) Longitudinal waves are created in a spring when the free end is moved back and forth parallel to the spring. (B) Transverse waves are created in a spring when the free end is moved up and down.

Hearing Waves in Air:Infrasonic

Longitudinal waves with frequencies below 20 Hz

UltrasonicLongitudinal waves with frequencies greater that 20,000 Hz

Since humans can only hear waves in the 20 – 20,000 Hz range, they hear neither infrasonic nor ultrasonic waves.

Waves move the eardrum in and out with the same frequency as the wave, which the brain interprets as sound.

Wave Terms.

Wave CrestThe maximum disturbance a wave will create from the resting

position

Wave troughMaximum displacement a wave will create in the opposite

direction from the resting position.

AmplitudeThe magnitude of the displacement to either the crest or the

trough.

PeriodThe time required for a wave to repeat itselfThis is the time that is required to move through one full wave

cycle.

Here are some terms associated with periodic waves. The wavelength is the distance from a part of one wave to the same part in the next wave, such as from one crest to the next. The amplitude is the displacement from the rest position. The period is the time required for a wave to repeat itself, that is the time for one complete wavelength to move past a given location.

WavelengthThe distance from one crest of a wave to the crest of

the next wave.Given the Greek symbol lambda ()

Wave EquationThe wave equation tells us that the relationship

between the velocity of sound waves and the frequency is:v=f

Sound Waves.

IntroductionThe movement of sound waves requires a medium

through which the waves can travel.The nature of the medium determines the velocity of

the sound through the mediumThis is due to the fact that the waves are propagated

through molecular interactions and is determined by:Inertia of the moleculesStrength of the interactions between molecules

(A) Spherical waves move outward from a sounding source much as a rapidly expanding balloon. This two-dimensional sketch shows the repeating condensation as spherical wave fronts. (B) Some distance from the source, a spherical wave front is considered a linear, or plane, wave front.

(A) Since sound travels faster in warmer air, a wave front becomes bent, or refracted, toward the earth's surface when the air is cooler near the surface. (B) When the air is warmer near the surface, a wave front is refracted upward, away from the surface.

Energy and Sound.

Loudness.The energy of a sound wave is called the wave

intensity and is measured in Watts per square meter.The intensity of wound is expressed on the decibel

scale, which relates to changes in loudness as perceived by the human ear.

ResonanceAll elastic objects have natural frequencies of

vibration that are determined by the materials they are made of and their shapes.

When energy is transferred at the natural frequencies, there is a dramatic increase of amplitude called resonance.

The natural frequencies are also called resonant frequencies.

When the frequency of an applied force, including the force of a sound wave, matches the natural frequency of an object, energy is transferred very efficiently. The condition is called resonance.

Different sounds that you hear include (A) noise, (B) pure tones, and (C) musical notes.

Sources of Sounds.

Vibrating Strings.Standing Waves

When reflected waves interfere with incoming wavesCreated by a patter on nodes and antinodes

NodesPlaces of destructive interference, which show no

disturbance

Standing waves in these open tubes have an antinode at the open end, where air is free to vibrate.

Standing sine wave patterns of air vibrating in an open tube. Note that both ends have anitnodes. Any whole number of multiples of the fundamental are therefore possible.

Sounds from Moving Sources.A moving source of sound or a moving observer

experiences an apparent shift of frequency called the Doppler Effect.

If the source is moving as fast or faster than the speed of sound, the sound waves pile up into a shock wave called a sonic boom.

A sonic boom sound very much like the pressure wave from an explosion

Now let us start checking our understanding about wave motion and sound:

1.What is the type of sound waves propogating in air?

a.Longitudinal only b.transverse onlyc.it can be either longitudinal or transver

sed.Non mechanical

2.What is the type of sound waves propogating in a solid?

a.Longitudinal wavesb.transverse wavesc.it can be either longitudinal or transver

sed.Non mehanical

3.Which waves don’t need a medium for propogation?

a.Sound wavesb.Light wavesc.earthquake wavesd.Wave on water surface

4.Earthquake waves are of which type?

a.Infrasonicb.Ultrasonicc.Supersonicd.Intrasonic

5.What is the range of wavelength of audible sound in air?

a.0.17m to 170 mb.0.17 to 17 mc.0.017 m to 17 md.0.017 m to 1.7 m

Lets read about oscillation

1.If A be the maximum displacement of the particle from its equilibrium position,then what is the distance travelled by a simple harmonic oscillator when it completes one oscillation?A. AB.2AC.3AD.4A

2.Propogation of wave transfers:

A.energy onlyB.matter onlyC.both energy and matterD.none of these

3.The period of a vibrating body of frequency 100Hz is

A.100 secB.10 secC.0.1 secD.0.01 sec

4.The SI unit of wavelength is

A.meterB.sC.meter/secD.Hertz

5.The time taken to complete one oscillation is called

A.time periodB.velocityC.frequencyD.wavelength

Lets Read about SOUND

1.Sound corresponding to which frequency is ultrasonic sound?

A.30 HzB.300 HzC.3000 HzD.30,000 Hz

2.What is full form of SONAR?

A.System of Navigation and researchB.Sound Navigation and RangingC.Sound of Natural Agriculture

ResearchD.Sound of Navigation and Research

3.Sound Travels faster in which medium?

A.SolidB.LiquidC.GasD.Both A and B

4.A medium transmits a sound wave by virtue of its?

A.elasticityB.inertiaC.densityD.both inertia and elasticity

5.If the time interval between original sound and reflected sound is more then 0.1 sec then originally sound and reflected can be heard clearly. This reflected sound is known as

A.ReflectionB.EchoC.ReverberationD.Both A and B

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