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Waves Definition

A wave is an energetic disturbance in a medium that doesn't include any net particle motion. Elastic deformation, a change in pressure, an electric or magnetic intensity, an electric potential, or a temperature change are a few examples.

There are certain fundamental characteristics of a wave. The distance separating two successively identical wave components is known as the wavelength. The greatest deviation from the neutral position is called the amplitude. This is an illustration of the wave's energy. An increase in amplitude carries more energy. The position of a specific point in the medium as it shifts as the wave travels is known as displacement. The highest displacement is the wave's amplitude.

Waves Definition

Period (T) is the time it takes for one wavelength to pass a location, and frequency is the number of repeats per second in Hertz (Hz). The speed at which a particular portion of the wave passes a place is known as the wave's velocity (v). A light wave travels at a speed of c.

Different Types of waves

1. Transverse waves:- Transverse waves are waves in which the medium moves perpendicular to the direction of the wave.

Transverse wave examples: Ocean waves (ripples of gravity waves, not sound through water), waves of light, S-wave seismic waves, instruments with strings, a tidal wave.

A crest is a transverse wave's highest point. A trough is an area which is its lowest point.

2. Longitudinal waves:- A longitudinal wave moves the medium's particles in the same direction and along the same axis as the wave.

Some illustrations of a longitudinal wave: Seismic waves of the P-type in sound, Wave of compression, Longitudinal wave components.

When particles are compressed, they are close together.

3. Medium waves:- A wave that requires a medium in order to spread. Examples of this include sound waves, slinky waves, and water waves.

4. Matter waves:- A wave is a term used to describe any moving item. When a stone is dropped into a body of water, the water is temporarily disturbed from its equilibrium positions while the wave is passing and then returns to its equilibrium positions.

5. Electromagnetic waves:- These waves are disturbances that may readily go through the vacuum and do not require any physical medium for propagation. They are created as a result of different magnetic and electric forces. electromagnetic waves are the cyclical shifts in magnetic and electric fields that they produce.

Formula of Wave Speed

It is the overall distance the wave has travelled in a specific time. The following is the formula for wave speed:

Wave speed = Distance Covered/Time Taken

Characterstics of Waves

The following are the main characteristics of waves:

  1. A phenomenon that transport energy is amplitude-wave. It is directly correlated with how much energy a wave carries. The height of the wave, expressed in metres, is its amplitude.
  2. A wave's wavelength is the separation between two identical places in neighbouring cycles of its crests. Also, metres are used to measure it.
  3. The time it takes for a particle in a medium to complete one full vibrational cycle is the period of a wave. Time units like seconds or minutes quantify the period because it is time itself.
  4. The quantity of waves that pass a spot in a certain time is known as a wave's frequency. Hertz (Hz), equal to one wave per second, is the unit of frequency.
  5. The frequency and period are opposites of each other.
  6. The distance travelled divided by the time of journey is a common way to express speed, which refers to how quickly an object moves. The wave's speed is the distance travelled by a certain point on a wave's crest.

Behaviour of Waves

Waves exhibit various fundamental phenomena. A wave is reflected when it hits a barrier during reflection. When a wave enters a medium with a different speed, it bends, known as refraction. Waves in diffraction spread out when they pass through tiny gaps and bend when they pass around small obstructions. When two waves collide in interference, they may interfere constructively, increasing the amplitude of the new wave relative to the original waves, or destructively, decreasing the amplitude of the new wave or even zeroing it out.


Angles of incidence and reflection are equal when waves strike a boundary and are reflected. The angle of incidence is the angle formed by a line drawn perpendicular to the reflecting barrier and the wave's direction of motion.


The characteristics of the medium a wave travels through affect its speed. Sound, for instance, travels through the water far more quickly than it does through air. A wave bends towards the perpendicular when it enters a medium at an angle where its speed would be slower. The reverse effect occurs when a wave enters a medium at an angle where its speed is enhanced. Snell's law of refraction can be used to describe this change in the case of light.


A wave can bend around an obstruction or pass through a small opening compared to the wave's wavelength before continuing on its path and spreading out. Diffraction is the name for this bending or spreading out.


The waves from two or more disturbance centres either can strengthen or cancel one another in different directions. The interference of waves is the name given to this occurrence. It is simple to imagine how this could occur. Take two sources in phase and create waves of the same wavelength; the waves' crests happen at the same moment at their sources. The crests reinforce each other when they reach a point P far from both origins. The troughs also appear at the same time and deepen. The same thing happens even if the distances to point P are not equal but vary by one or more full wavelengths. The intensity of the resulting wave is reduced if, however, the distances are offset by a half-wavelength or an odd number of half-wavelengths, causing the crests of one wave to coincide with the troughs of the other. When two such waves have the same intensity, they fully cancel one another. Intermediate conditions can occur in directions where the two waves have travelled at different wavelengths, with the waves tending to either reinforce or cancel one another.

Doppler effect

An observer detects a change in the wave's frequency when the wave's source moves concerning them. The Doppler effect is given to this alteration in honour of its discoverer, Austrian physicist Christian Doppler.

Let us think of a source emitting a wave of frequency v, such as light or sound, and travelling away from an observer at a velocity of v. The calculation reveals that the observer will receive the light waves at a frequency of v(1-v/c), where c is the wave's velocity. The light waves will reach the observer at longer intervals than if the observer were at rest. The observer will perceive the wave's frequency as slightly lower than if the source were at rest. The frequency will increase if the source gets closer. The observer will perceive the wave's frequency as slightly lower than if the source were at rest. The frequency will increase if the source is getting closer.

Standing Waves

A wave experiences reflection and interference only when contained in a small area. Let us consider a tube with length l as an illustration. Any disturbance in the tube's air will be reflected from both ends, creating a series of waves generally moving in both directions. They have to be periodic waves with frequencies set by the boundary conditions at the end of the tube based on the geometry of the situation and the finite constant value of the acoustic velocity. The allowable frequencies of the waves in the tube are v = nv/2l, where n is any integer and v is the acoustic velocity in the tube, and the allowed frequencies fulfil sin kl = 0. These harmonic wave frequencies can occur inside the tube while still meeting the boundary requirements at the ends. These are the characteristic frequencies or regular air column vibration modes. The maximum frequency that can occur in the tube yet meet the boundary criteria at the ends is v = v/2l for fundamental frequency (n = 1). These are the characteristic frequencies or regular air column vibration modes. v = v/2l is the fundamental frequency (n = 1).

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