What are Waves?
A wave transmits information or energy from one point to another in the form of signals, but no material object makes this journey. The frequency of a wave is obtained by including a factor of time in the mix. We are completely dependent on waves for all of our wireless communications.
For example, you make a call to your friend in another city with your mobile phone, the entire communication is happening via audio but the entire process of transmission of a signal from the talker to the receiver occurs as a waveform. The phone converts your voice into an electrical signal which then propagates either through copper wires or through antennae in wireless communication.
Wave is a flow or transfer of energy in the form of oscillation through a medium – space or mass. Sea waves or tides, a sound which we hear, a photon of light travelling and even the movement of small plants blown by the wind are all examples of different types of waves. A simple wave illustration is as follows.
Types of Waves in Physics
Different types of waves have a different set of characteristics. Based on the orientation of particle motion and direction of energy, there are three categories:
- Mechanical waves
- Electromagnetic waves
- Matter waves
- A mechanical wave is a wave that is an oscillation of matter and is responsible for the transfer of energy through a medium.
- The distance of the wave’s propagation is limited by the medium of transmission. In this case, the oscillating material moves about a fixed point, and there is very little translational motion. One intriguing property of mechanical wave is the way they are measured, which is given by displacement divided by wavelength. When this dimensionless factor is 1, it results in the generation of harmonic effects; for example, waves break on the beach when this factor exceeds 1, resulting in turbulence.
There are two types of mechanical waves:
- Longitudinal waves – In this type of wave, the movement of the particle are parallel to the motion of the energy i.e. the displacement of the medium is in the same direction to which the wave is moving. Example – Sound Waves, Pressure Waves.
- Transverse waves – When the movement of the particles is at right angles or perpendicular to the motion of the energy, then this type of wave is known as Transverse wave. Light is an example of a transverse wave. Some of the other examples are – ‘Polarized’ waves & Electromagnetic waves.
Water waves are an example of a combination of both longitudinal and transverse motions.
- Surface waves – In this type, the particles travel in a circular motion. These waves usually occur at interfaces. Waves in the ocean and ripples in a cup of water are examples of such waves.
Learn more about S waves here.
- Electromagnetic waves are created by a fusion of electric and magnetic fields. The light you see, the colours around you are visible because of electromagnetic waves.
- One interesting property here is that unlike mechanical waves, electromagnetic waves do not need a medium to travel. All electromagnetic waves travel through a vacuum at the same speed, 299,792,458 ms-1.
Following are the different types of electromagnetic waves:
- Radio waves
- Ultraviolet waves
Learn more about Sound waves here.
Difference Between Mechanical Wave and Non-Mechanical Wave
|Mechanical Wave||Non-Mechanical Wave|
|Mechanical waves are waves that need a medium for propagation.||Non-mechanical waves are waves that do not need a medium for propagation.|
|Sound waves, water waves and seismic waves are some examples of mechanical waves.||The electromagnetic wave is the only non-mechanical wave.|
|Mechanical waves cannot travel through vacuum||Non-mechanical waves can travel through vacuum|
- This concept is a little complicated to understand. The dual nature of matter; its ability to exist both as a particle and a wave was first brought to light by the founders of the field of Quantum Physics.
- For example, a beam of electrons can be diffracted just like any other beam of electromagnetic radiation or water wave. This property of matter was brought forward by Louis de Broglie’s Hypothesis.
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