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
➤ 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.
➤ 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.
• 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|
• 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|
• 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|
• Sound on a Spring
• Sound waves
• Ultrasound waves
• Seismic P-waves
• 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 – ✕