# Types of Waves

For various competitive exams like SSC, Banking, UPSC, Railways, State Level Exams general science is a vital subject. To cover all the topics of general science, we divided each chapter into many subtopics. Here the topic ‘Types of waves ‘ comes under the chapter “wave motion and sound waves” of Physics.

## What is a Wave?

➤ A wave is a form of periodic disturbance of particles that travels through a medium or without medium from one location to another location.

➤ Here ‘periodic’ means the displacement of the particles in a regular and organized manner.

➤ And the ‘disturbance’ means the displacement of the particles from its original position or equilibrium position or rest position.

Disturbance can occur in the form of
Displacement (Example – Waves on a string)
◘ Pressure (Example – Sound waves formed by Tuning fork)
◘ Density (Example – Sound Waves, Compression / Rarefraction)
◘ Electric & Magnetic field. (Example – Electromagnetic waves)

➤ In a wave the particle can be displaced upwards or downwards and forwards or backwards

➤ But once the particle displaced from its rest position, after some time it is returned to its original equilibrium position.
Waves is a form of energy, through its each particle transfer its pressure and energy to the adjacent particles.

## Types of Waves

Based on the medium there are two types of waves.
♦  Mechanical waves
•  Mechanical waves require a medium for propagation, they cannot propagate through vacuum like Light waves.

♦ Non-mechanical Waves
• Non-mechanical Waves does not require a medium, they can travel through vacuum.
Example – All Electromagnetic waves like Light waves, radio waves, X-rays.
• In vacuum, all electromagnetic waves have the same speed c, whose value is – c = 10^8 ms^–1

Based on the vibrations of the particle there are two types of waves ..
♦ Longitudinal Waves
♦ Transverse Waves

### Longitudinal Waves

➤ A waves in which the vibration of the particles of the medium is same as the direction of the propagation of wave is called longitudinal wave.

➤ Longitudinal waves can be propagated through all the three media such as solids, liquids and gases.

➤ The Waves produced and propagated in Air and spring respectively, are longitudinal waves.

➤ Examples of Longitudinal waves
◘ Sound Waves
◘ Ultrasound waves.
◘ Seismic P-waves.
◘ Waves on a spring

➤ Waves on a Spring
◘ Waves in a spring travels through Compression and raredactions.
◘ Compression –
• When the coils are closer to each other than its equilibrium position in original position , compressions (dense part of the coils) are observed

◘ Rarefactions –
• When the coils are farther to each other than its equilibrium position in original position , Rarefactions(lighter part of the coils) are observed

➤ Waves in Air
◘ When a longitudinal wave (for example sound waves) propagated through air the density of air changes continuously due to compressions and rarefactions.

### Transverse Waves

➤ In a Transverse Waves the particles of the medium vibrate perpendicular to the direction of the propagation of waves.

➤ Transverse Waves propagate only in Solids and liquid surfaces. It cannot propagate through gases or liquids. (Except – liquid surface)

➤ Example of Transverse Waves
Light waves (But light waves is an electro magnetic waves or nonmechanical waves)

The waves produced in a String or a rope.
◘ The cirular ripple waves of water (when a ston or Pieces of bricks dropped in the pond water) formed on the surface of the water.

➤ Transverse Waves in a rope
Transverse waves in a rope propagate through crest and trough.

◘ The particles in a transverse waves moved from its original position in the vertical direction that means upwards and downwards.

◘ Crest
• A Crest is formed when the particles move in maximum position upwards from its original position.

◘ Trough –
• A trough. is formed when the particles move in maximum position downwards from its original position.

## Difference between Longitudinal and Transverse waves

Parameter Longitudinal waves Transverse waves
Movement The particle moves in the direction of the wave motions The particles moves, perpendicular to the direction of the wave motions
Dimension This wave acts in one dimension This wave acts in two dimensions
Composition The Longitudinal wave moves through compressions and rarefactions. Transverse wave moves through crests and troughs
Medium Longitudinal wave propagated through solids, liquids and gases. Transverse wave propagated through solids and liquid’s surface.
Example P wave of earthquake, Sound wave S wave of earthquake, Radio wave, Light wave

## Summery

• Waves is a form of energy.
• In a wave the energy transported by particles.
• Particles do not travel .
• Each particles transport its energy to adjacent particles.
• A wave can travel with or without any media
• The particles only oscilating.

#### ❖Types of Waves

Based on medium
Mechanical waves Non-mechanical waves
Required a medium to travel Medium do not required
Examples :-
• Sound Waves
• Jump rope wave
• Water waves
• Seismic waves.
Examples :- All Electro Megnetic wave
Based on vibration of the particles
Longitudinal waves Transverse waves
Vibration of particles same as the direction of wave motions. Vibration of particles perpendicular to the direction of wave motions.
Travel through – Solids, Liquids and Gases. Travel through – Solids and Liquid surface
Examples –
• Sound on a Spring
• Sound waves
• Ultrasound waves
• Seismic P-waves
Examples –
• Waves on a string / rope
• Ripples on the surface of water
• Earthquake S wave• All Electromagnetic waves like – Light waves, microwaves, radio waves.
Sound waves Light waves
• Mechanical waves – ✓
• Non-Mechanical waves – ✕
• Transverse waves – ✕
• Longitudinal waves – ✓
• Mechanical waves – ✕
• Non-Mechanical waves – ✓
• Transverse waves – ✓
• Longitudinal waves – ✕